Production of new arrangements of DNA by various mechanisms such as assortment and segregation, CROSSING OVER; GENE CONVERSION; GENETIC TRANSFORMATION; GENETIC CONJUGATION; GENETIC TRANSDUCTION; or mixed infection of viruses.
An exchange of DNA between matching or similar sequences.
The reciprocal exchange of segments at corresponding positions along pairs of homologous CHROMOSOMES by symmetrical breakage and crosswise rejoining forming cross-over sites (HOLLIDAY JUNCTIONS) that are resolved during CHROMOSOME SEGREGATION. Crossing-over typically occurs during MEIOSIS but it may also occur in the absence of meiosis, for example, with bacterial chromosomes, organelle chromosomes, or somatic cell nuclear chromosomes.
A DNA-binding protein that mediates DNA REPAIR of double strand breaks, and HOMOLOGOUS RECOMBINATION.
The process by which the V (variable), D (diversity), and J (joining) segments of IMMUNOGLOBULIN GENES or T-CELL RECEPTOR GENES are assembled during the development of LYMPHOID CELLS using NONHOMOLOGOUS DNA END-JOINING.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
A type of CELL NUCLEUS division, occurring during maturation of the GERM CELLS. Two successive cell nucleus divisions following a single chromosome duplication (S PHASE) result in daughter cells with half the number of CHROMOSOMES as the parent cells.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
Recombinases that insert exogenous DNA into the host genome. Examples include proteins encoded by the POL GENE of RETROVIRIDAE and also by temperate BACTERIOPHAGES, the best known being BACTERIOPHAGE LAMBDA.
The reconstruction of a continuous two-stranded DNA molecule without mismatch from a molecule which contained damaged regions. The major repair mechanisms are excision repair, in which defective regions in one strand are excised and resynthesized using the complementary base pairing information in the intact strand; photoreactivation repair, in which the lethal and mutagenic effects of ultraviolet light are eliminated; and post-replication repair, in which the primary lesions are not repaired, but the gaps in one daughter duplex are filled in by incorporation of portions of the other (undamaged) daughter duplex. Excision repair and post-replication repair are sometimes referred to as "dark repair" because they do not require light.
Theoretical representations that simulate the behavior or activity of genetic processes or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.
A Rec A recombinase found in eukaryotes. Rad51 is involved in DNA REPAIR of double-strand breaks.
The asymmetrical segregation of genes during replication which leads to the production of non-reciprocal recombinant strands and the apparent conversion of one allele into another. Thus, e.g., the meiotic products of an Aa individual may be AAAa or aaaA instead of AAaa, i.e., the A allele has been converted into the a allele or vice versa.
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
A broad category of enzymes that are involved in the process of GENETIC RECOMBINATION.
Enzymes that catalyze the incorporation of deoxyribonucleotides into a chain of DNA. EC 2.7.7.-.
Any method used for determining the location of and relative distances between genes on a chromosome.
Recombinases involved in the rearrangement of immunity-related GENES such as IMMUNOGLOBULIN GENES and T-CELL RECEPTOR GENES.
Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.
Interruptions in the sugar-phosphate backbone of DNA, across both strands adjacently.
Proteins which bind to DNA. The family includes proteins which bind to both double- and single-stranded DNA and also includes specific DNA binding proteins in serum which can be used as markers for malignant diseases.
The process of cumulative change at the level of DNA; RNA; and PROTEINS, over successive generations.
Gene rearrangement of the B-lymphocyte which results in a substitution in the type of heavy-chain constant region that is expressed. This allows the effector response to change while the antigen binding specificity (variable region) remains the same. The majority of class switching occurs by a DNA recombination event but it also can take place at the level of RNA processing.
The relationships of groups of organisms as reflected by their genetic makeup.
A species of the genus SACCHAROMYCES, family Saccharomycetaceae, order Saccharomycetales, known as "baker's" or "brewer's" yeast. The dried form is used as a dietary supplement.
A family of recombinases initially identified in BACTERIA. They catalyze the ATP-driven exchange of DNA strands in GENETIC RECOMBINATION. The product of the reaction consists of a duplex and a displaced single-stranded loop, which has the shape of the letter D and is therefore called a D-loop structure.
Genotypic differences observed among individuals in a population.
Deoxyribonucleic acid that makes up the genetic material of fungi.
Variant forms of the same gene, occupying the same locus on homologous CHROMOSOMES, and governing the variants in production of the same gene product.
Specific loci on both the bacterial DNA (attB) and the phage DNA (attP) which delineate the sites where recombination takes place between them, as the phage DNA becomes integrated (inserted) into the BACTERIAL DNA during LYSOGENY.
Structures within the nucleus of fungal cells consisting of or containing DNA, which carry genetic information essential to the cell.
A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.
A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).
A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.
Proteins that catalyze the unwinding of duplex DNA during replication by binding cooperatively to single-stranded regions of DNA or to short regions of duplex DNA that are undergoing transient opening. In addition DNA helicases are DNA-dependent ATPases that harness the free energy of ATP hydrolysis to translocate DNA strands.
A segment of the immunoglobulin heavy chains, encoded by the IMMUNOGLOBULIN HEAVY CHAIN GENES in the J segment where, during the maturation of B-LYMPHOCYTES; the gene segment for the variable region upstream is joined to a constant region gene segment downstream. The exact position of joining of the two gene segments is variable and contributes to ANTIBODY DIVERSITY. It is distinguished from the IMMUNOGLOBULIN J CHAINS; a separate polypeptide that serves as a linkage piece in polymeric IGA or IGM.
The alignment of CHROMOSOMES at homologous sequences.
Injuries to DNA that introduce deviations from its normal, intact structure and which may, if left unrepaired, result in a MUTATION or a block of DNA REPLICATION. These deviations may be caused by physical or chemical agents and occur by natural or unnatural, introduced circumstances. They include the introduction of illegitimate bases during replication or by deamination or other modification of bases; the loss of a base from the DNA backbone leaving an abasic site; single-strand breaks; double strand breaks; and intrastrand (PYRIMIDINE DIMERS) or interstrand crosslinking. Damage can often be repaired (DNA REPAIR). If the damage is extensive, it can induce APOPTOSIS.
A phenotypically recognizable genetic trait which can be used to identify a genetic locus, a linkage group, or a recombination event.
Deliberate breeding of two different individuals that results in offspring that carry part of the genetic material of each parent. The parent organisms must be genetically compatible and may be from different varieties or closely related species.
Genes involved in activating the enzyme VDJ recombinase. RAG-1 is located on chromosome 11 in humans (chromosome 2 in mice) and is expressed exclusively in maturing lymphocytes.
A family of enzymes that catalyze the exonucleolytic cleavage of DNA. It includes members of the class EC 3.1.11 that produce 5'-phosphomonoesters as cleavage products.
The co-inheritance of two or more non-allelic GENES due to their being located more or less closely on the same CHROMOSOME.
The ordered rearrangement of gene regions by DNA recombination such as that which occurs normally during development.
A site located in the INTRONS at the 5' end of each constant region segment of a immunoglobulin heavy-chain gene where recombination (or rearrangement) occur during IMMUNOGLOBULIN CLASS SWITCHING. Ig switch regions are found on genes encoding all five classes (IMMUNOGLOBULIN ISOTYPES) of IMMUNOGLOBULIN HEAVY CHAINS.
In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)
Sequences of DNA or RNA that occur in multiple copies. There are several types: INTERSPERSED REPETITIVE SEQUENCES are copies of transposable elements (DNA TRANSPOSABLE ELEMENTS or RETROELEMENTS) dispersed throughout the genome. TERMINAL REPEAT SEQUENCES flank both ends of another sequence, for example, the long terminal repeats (LTRs) on RETROVIRUSES. Variations may be direct repeats, those occurring in the same direction, or inverted repeats, those opposite to each other in direction. TANDEM REPEAT SEQUENCES are copies which lie adjacent to each other, direct or inverted (INVERTED REPEAT SEQUENCES).
The integration of exogenous DNA into the genome of an organism at sites where its expression can be suitably controlled. This integration occurs as a result of homologous recombination.
A temperate inducible phage and type species of the genus lambda-like viruses, in the family SIPHOVIRIDAE. Its natural host is E. coli K12. Its VIRION contains linear double-stranded DNA with single-stranded 12-base 5' sticky ends. The DNA circularizes on infection.
The process by which a DNA molecule is duplicated.
The sequential correspondence of nucleotides in one nucleic acid molecule with those of another nucleic acid molecule. Sequence homology is an indication of the genetic relatedness of different organisms and gene function.
Proteins obtained from the species SACCHAROMYCES CEREVISIAE. The function of specific proteins from this organism are the subject of intense scientific interest and have been used to derive basic understanding of the functioning similar proteins in higher eukaryotes.
Deoxyribonucleic acid that makes up the genetic material of bacteria.
The complete genetic complement contained in a DNA or RNA molecule in a virus.
An ATP-dependent exodeoxyribonuclease that cleaves in either the 5'- to 3'- or the 3'- to 5'-direction to yield 5'-phosphooligonucleotides. It is primarily found in BACTERIA.
The three-part structure of ribbon-like proteinaceous material that serves to align and join the paired homologous CHROMOSOMES. It is formed during the ZYGOTENE STAGE of the first meiotic division. It is a prerequisite for CROSSING OVER.
Use of restriction endonucleases to analyze and generate a physical map of genomes, genes, or other segments of DNA.
Repair of DNA DAMAGE by exchange of DNA between matching sequences, usually between the allelic DNA (ALLELES) of sister chromatids.
A single chain of deoxyribonucleotides that occurs in some bacteria and viruses. It usually exists as a covalently closed circle.
A cross-shaped DNA structure that can be observed under the electron microscope. It is formed by the incomplete exchange of strands between two double-stranded helices or by complementary INVERTED REPEAT SEQUENCES that refold into hairpin loops on opposite strands across from each other.
A group of enzymes catalyzing the endonucleolytic cleavage of DNA. They include members of EC 3.1.21.-, EC 3.1.22.-, EC 3.1.23.- (DNA RESTRICTION ENZYMES), EC 3.1.24.- (DNA RESTRICTION ENZYMES), and EC 3.1.25.-.
Differential and non-random reproduction of different genotypes, operating to alter the gene frequencies within a population.
Discrete segments of DNA which can excise and reintegrate to another site in the genome. Most are inactive, i.e., have not been found to exist outside the integrated state. DNA transposable elements include bacterial IS (insertion sequence) elements, Tn elements, the maize controlling elements Ac and Ds, Drosophila P, gypsy, and pogo elements, the human Tigger elements and the Tc and mariner elements which are found throughout the animal kingdom.
The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.
A method (first developed by E.M. Southern) for detection of DNA that has been electrophoretically separated and immobilized by blotting on nitrocellulose or other type of paper or nylon membrane followed by hybridization with labeled NUCLEIC ACID PROBES.
A genetic rearrangement through loss of segments of DNA or RNA, bringing sequences which are normally separated into close proximity. This deletion may be detected using cytogenetic techniques and can also be inferred from the phenotype, indicating a deletion at one specific locus.
Deoxyribonucleic acid that makes up the genetic material of viruses.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
An aberration in which a chromosomal segment is deleted and reinserted in the same place but turned 180 degrees from its original orientation, so that the gene sequence for the segment is reversed with respect to that of the rest of the chromosome.
Ordered rearrangement of B-lymphocyte variable gene regions coding for the IMMUNOGLOBULIN CHAINS, thereby contributing to antibody diversity. It occurs during the differentiation of the IMMATURE B-LYMPHOCYTES.
In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.
The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.
The functional hereditary units of FUNGI.
Double-stranded nucleic acid molecules (DNA-DNA or DNA-RNA) which contain regions of nucleotide mismatches (non-complementary). In vivo, these heteroduplexes can result from mutation or genetic recombination; in vitro, they are formed by nucleic acid hybridization. Electron microscopic analysis of the resulting heteroduplexes facilitates the mapping of regions of base sequence homology of nucleic acids.
Structures within the nucleus of bacterial cells consisting of or containing DNA, which carry genetic information essential to the cell.
An exchange of segments between the sister chromatids of a chromosome, either between the sister chromatids of a meiotic tetrad or between the sister chromatids of a duplicated somatic chromosome. Its frequency is increased by ultraviolet and ionizing radiation and other mutagenic agents and is particularly high in BLOOM SYNDROME.
The chromosomal constitution of cells, in which each type of CHROMOSOME is represented twice. Symbol: 2N or 2X.
Enzymes that catalyze the hydrolysis of the internal bonds and thereby the formation of polynucleotides or oligonucleotides from ribo- or deoxyribonucleotide chains. EC 3.1.-.
Established cell cultures that have the potential to propagate indefinitely.
A family of structurally-related DNA helicases that play an essential role in the maintenance of genome integrity. RecQ helicases were originally discovered in E COLI and are highly conserved across both prokaryotic and eukaryotic organisms. Genetic mutations that result in loss of RecQ helicase activity gives rise to disorders that are associated with CANCER predisposition and premature aging.
The chromosomal constitution of cells, in which each type of CHROMOSOME is represented once. Symbol: N.
Enzymes that are involved in the reconstruction of a continuous two-stranded DNA molecule without mismatch from a molecule, which contained damaged regions.
An increased tendency of the GENOME to acquire MUTATIONS when various processes involved in maintaining and replicating the genome are dysfunctional.
The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.
DNA molecules capable of autonomous replication within a host cell and into which other DNA sequences can be inserted and thus amplified. Many are derived from PLASMIDS; BACTERIOPHAGES; or VIRUSES. They are used for transporting foreign genes into recipient cells. Genetic vectors possess a functional replicator site and contain GENETIC MARKERS to facilitate their selective recognition.
Change brought about to an organisms genetic composition by unidirectional transfer (TRANSFECTION; TRANSDUCTION, GENETIC; CONJUGATION, GENETIC, etc.) and incorporation of foreign DNA into prokaryotic or eukaryotic cells by recombination of part or all of that DNA into the cell's genome.
Proteins found in the nucleus of a cell. Do not confuse with NUCLEOPROTEINS which are proteins conjugated with nucleic acids, that are not necessarily present in the nucleus.
Short sequences (generally about 10 base pairs) of DNA that are complementary to sequences of messenger RNA and allow reverse transcriptases to start copying the adjacent sequences of mRNA. Primers are used extensively in genetic and molecular biology techniques.
The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.
Biologically active DNA which has been formed by the in vitro joining of segments of DNA from different sources. It includes the recombination joint or edge of a heteroduplex region where two recombining DNA molecules are connected.
The functional hereditary units of BACTERIA.
Genes encoding the different subunits of the IMMUNOGLOBULINS, for example the IMMUNOGLOBULIN LIGHT CHAIN GENES and the IMMUNOGLOBULIN HEAVY CHAIN GENES. The heavy and light immunoglobulin genes are present as gene segments in the germline cells. The completed genes are created when the segments are shuffled and assembled (B-LYMPHOCYTE GENE REARRANGEMENT) during B-LYMPHOCYTE maturation. The gene segments of the human light and heavy chain germline genes are symbolized V (variable), J (joining) and C (constant). The heavy chain germline genes have an additional segment D (diversity).
Mutagenesis where the mutation is caused by the introduction of foreign DNA sequences into a gene or extragenic sequence. This may occur spontaneously in vivo or be experimentally induced in vivo or in vitro. Proviral DNA insertions into or adjacent to a cellular proto-oncogene can interrupt GENETIC TRANSLATION of the coding sequences or interfere with recognition of regulatory elements and cause unregulated expression of the proto-oncogene resulting in tumor formation.
That region of the immunoglobulin molecule that varies in its amino acid sequence and composition, and comprises the binding site for a specific antigen. It is located at the N-terminus of the Fab fragment of the immunoglobulin. It includes hypervariable regions (COMPLEMENTARITY DETERMINING REGIONS) and framework regions.
Process of generating a genetic MUTATION. It may occur spontaneously or be induced by MUTAGENS.
The genetic constitution of individuals with respect to one member of a pair of allelic genes, or sets of genes that are closely linked and tend to be inherited together such as those of the MAJOR HISTOCOMPATIBILITY COMPLEX.
The spatial arrangement of the atoms of a nucleic acid or polynucleotide that results in its characteristic 3-dimensional shape.
Proteins found in any species of fungus.
A type of chromosomal aberration involving DNA BREAKS. Chromosome breakage can result in CHROMOSOMAL TRANSLOCATION; CHROMOSOME INVERSION; or SEQUENCE DELETION.
Proteins found in any species of bacterium.
Nonrandom association of linked genes. This is the tendency of the alleles of two separate but already linked loci to be found together more frequently than would be expected by chance alone.
The discipline studying genetic composition of populations and effects of factors such as GENETIC SELECTION, population size, MUTATION, migration, and GENETIC DRIFT on the frequencies of various GENOTYPES and PHENOTYPES using a variety of GENETIC TECHNIQUES.
Enzyme systems containing a single subunit and requiring only magnesium for endonucleolytic activity. The corresponding modification methylases are separate enzymes. The systems recognize specific short DNA sequences and cleave either within, or at a short specific distance from, the recognition sequence to give specific double-stranded fragments with terminal 5'-phosphates. Enzymes from different microorganisms with the same specificity are called isoschizomers. EC
That portion of the electromagnetic spectrum immediately below the visible range and extending into the x-ray frequencies. The longer wavelengths (near-UV or biotic or vital rays) are necessary for the endogenous synthesis of vitamin D and are also called antirachitic rays; the shorter, ionizing wavelengths (far-UV or abiotic or extravital rays) are viricidal, bactericidal, mutagenic, and carcinogenic and are used as disinfectants.
Enzymes that recombine DNA segments by a process which involves the formation of a synapse between two DNA helices, the cleavage of single strands from each DNA helix and the ligation of a DNA strand from one DNA helix to the other. The resulting DNA structure is called a Holliday junction which can be resolved by DNA REPLICATION or by HOLLIDAY JUNCTION RESOLVASES.
Lymphoid cells concerned with humoral immunity. They are short-lived cells resembling bursa-derived lymphocytes of birds in their production of immunoglobulin upon appropriate stimulation.
The process of cumulative change over successive generations through which organisms acquire their distinguishing morphological and physiological characteristics.
Deletion of sequences of nucleic acids from the genetic material of an individual.
A type of CELL NUCLEUS division by means of which the two daughter nuclei normally receive identical complements of the number of CHROMOSOMES of the somatic cells of the species.
An alkylating agent in cancer therapy that may also act as a mutagen by interfering with and causing damage to DNA.
Proteins obtained from ESCHERICHIA COLI.
The largest of polypeptide chains comprising immunoglobulins. They contain 450 to 600 amino acid residues per chain, and have molecular weights of 51-72 kDa.
A genus of ascomycetous fungi of the family Schizosaccharomycetaceae, order Schizosaccharomycetales.
A species of temperate bacteriophage in the genus P1-like viruses, family MYOVIRIDAE, which infects E. coli. It is the largest of the COLIPHAGES and consists of double-stranded DNA, terminally redundant, and circularly permuted.
A terminal section of a chromosome which has a specialized structure and which is involved in chromosomal replication and stability. Its length is believed to be a few hundred base pairs.
Proteins found in any species of virus.
Exons that are created in vivo during LYMPHOCYTE maturation from the V, D, and J gene segments of immunoglobulin superfamily genes (e.g., the IMMUNOGLOBULIN HEAVY CHAIN GENES, or the T-CELL RECEPTOR BETA GENES or T-CELL RECEPTOR GAMMA GENES ) by the VDJ RECOMBINASE system.
The failure of homologous CHROMOSOMES or CHROMATIDS to segregate during MITOSIS or MEIOSIS with the result that one daughter cell has both of a pair of parental chromosomes or chromatids and the other has none.
Directed modification of the gene complement of a living organism by such techniques as altering the DNA, substituting genetic material by means of a virus, transplanting whole nuclei, transplanting cell hybrids, etc.
The regular and simultaneous occurrence in a single interbreeding population of two or more discontinuous genotypes. The concept includes differences in genotypes ranging in size from a single nucleotide site (POLYMORPHISM, SINGLE NUCLEOTIDE) to large nucleotide sequences visible at a chromosomal level.
A test used to determine whether or not complementation (compensation in the form of dominance) will occur in a cell with a given mutant phenotype when another mutant genome, encoding the same mutant phenotype, is introduced into that cell.
An enzyme that catalyzes the deamination of cytidine, forming uridine. EC
The genetic complement of an organism, including all of its GENES, as represented in its DNA, or in some cases, its RNA.
The degree of similarity between sequences. Studies of AMINO ACID SEQUENCE HOMOLOGY and NUCLEIC ACID SEQUENCE HOMOLOGY provide useful information about the genetic relatedness of genes, gene products, and species.
Enzymes that regulate the topology of DNA by actions such as breaking, relaxing, passing, and rejoining strands of DNA in cells. These enzymes are important components of the DNA replication system. They are classified by their substrate specificities. DNA TOPOISOMERASE I enzymes act on a single strand of DNA. DNA TOPOISOMERASE II enzymes act on double strands of DNA.
A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms.
Enzymes that are part of the restriction-modification systems. They catalyze the endonucleolytic cleavage of DNA sequences which lack the species-specific methylation pattern in the host cell's DNA. Cleavage yields random or specific double-stranded fragments with terminal 5'-phosphates. The function of restriction enzymes is to destroy any foreign DNA that invades the host cell. Most have been studied in bacterial systems, but a few have been found in eukaryotic organisms. They are also used as tools for the systematic dissection and mapping of chromosomes, in the determination of base sequences of DNAs, and have made it possible to splice and recombine genes from one organism into the genome of another. EC 3.21.1.
An individual having different alleles at one or more loci regarding a specific character.
Enzymes that recognize CRUCIFORM DNA structures and introduce paired incisions that help to resolve the structure into two DNA helices.
Complex nucleoprotein structures which contain the genomic DNA and are part of the CELL NUCLEUS of PLANTS.
Proteins that control the CELL DIVISION CYCLE. This family of proteins includes a wide variety of classes, including CYCLIN-DEPENDENT KINASES, mitogen-activated kinases, CYCLINS, and PHOSPHOPROTEIN PHOSPHATASES as well as their putative substrates such as chromatin-associated proteins, CYTOSKELETAL PROTEINS, and TRANSCRIPTION FACTORS.
A set of genes descended by duplication and variation from some ancestral gene. Such genes may be clustered together on the same chromosome or dispersed on different chromosomes. Examples of multigene families include those that encode the hemoglobins, immunoglobulins, histocompatibility antigens, actins, tubulins, keratins, collagens, heat shock proteins, salivary glue proteins, chorion proteins, cuticle proteins, yolk proteins, and phaseolins, as well as histones, ribosomal RNA, and transfer RNA genes. The latter three are examples of reiterated genes, where hundreds of identical genes are present in a tandem array. (King & Stanfield, A Dictionary of Genetics, 4th ed)
The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.
A form of gene interaction whereby the expression of one gene interferes with or masks the expression of a different gene or genes. Genes whose expression interferes with or masks the effects of other genes are said to be epistatic to the effected genes. Genes whose expression is affected (blocked or masked) are hypostatic to the interfering genes.
The class of heavy chains found in IMMUNOGLOBULIN M. They have a molecular weight of approximately 72 kDa and they contain about 57 amino acid residues arranged in five domains and have more oligosaccharide branches and a higher carbohydrate content than the heavy chains of IMMUNOGLOBULIN G.
Reproductive bodies produced by fungi.
Interruptions in the sugar-phosphate backbone of DNA.
The female sex chromosome, being the differential sex chromosome carried by half the male gametes and all female gametes in human and other male-heterogametic species.
Actual loss of portion of a chromosome.
The record of descent or ancestry, particularly of a particular condition or trait, indicating individual family members, their relationships, and their status with respect to the trait or condition.
The repair of DOUBLE-STRAND DNA BREAKS by rejoining the broken ends of DNA to each other directly.
The heritable modification of the properties of a competent bacterium by naked DNA from another source. The uptake of naked DNA is a naturally occuring phenomenon in some bacteria. It is often used as a GENE TRANSFER TECHNIQUE.
Chromosomal, biochemical, intracellular, and other methods used in the study of genetics.
Immunologically detectable substances found in the CELL NUCLEUS.
A group of enzymes which catalyze the hydrolysis of ATP. The hydrolysis reaction is usually coupled with another function such as transporting Ca(2+) across a membrane. These enzymes may be dependent on Ca(2+), Mg(2+), anions, H+, or DNA.
The stage in the first meiotic prophase, following ZYGOTENE STAGE, when CROSSING OVER between homologous CHROMOSOMES begins.
A single-stranded DNA-binding protein that is found in EUKARYOTIC CELLS. It is required for DNA REPLICATION; DNA REPAIR; and GENETIC RECOMBINATION.
The functional hereditary units of VIRUSES.
Ordered rearrangement of T-cell variable gene regions coding for the antigen receptors.
Proteins obtained from the species Schizosaccharomyces pombe. The function of specific proteins from this organism are the subject of intense scientific interest and have been used to derive basic understanding of the functioning similar proteins in higher eukaryotes.
Any of the covalently closed DNA molecules found in bacteria, many viruses, mitochondria, plastids, and plasmids. Small, polydisperse circular DNA's have also been observed in a number of eukaryotic organisms and are suggested to have homology with chromosomal DNA and the capacity to be inserted into, and excised from, chromosomal DNA. It is a fragment of DNA formed by a process of looping out and deletion, containing a constant region of the mu heavy chain and the 3'-part of the mu switch region. Circular DNA is a normal product of rearrangement among gene segments encoding the variable regions of immunoglobulin light and heavy chains, as well as the T-cell receptor. (Riger et al., Glossary of Genetics, 5th ed & Segen, Dictionary of Modern Medicine, 1992)
Ribonucleic acid that makes up the genetic material of viruses.
A parasexual process in BACTERIA; ALGAE; FUNGI; and ciliate EUKARYOTA for achieving exchange of chromosome material during fusion of two cells. In bacteria, this is a uni-directional transfer of genetic material; in protozoa it is a bi-directional exchange. In algae and fungi, it is a form of sexual reproduction, with the union of male and female gametes.
The phenomenon of immense variability characteristic of ANTIBODIES. It enables the IMMUNE SYSTEM to react specifically against the essentially unlimited kinds of ANTIGENS it encounters. Antibody diversity is accounted for by three main theories: (1) the Germ Line Theory, which holds that each antibody-producing cell has genes coding for all possible antibody specificities, but expresses only the one stimulated by antigen; (2) the Somatic Mutation Theory, which holds that antibody-producing cells contain only a few genes, which produce antibody diversity by mutation; and (3) the Gene Rearrangement Theory, which holds that antibody diversity is generated by the rearrangement of IMMUNOGLOBULIN VARIABLE REGION gene segments during the differentiation of the ANTIBODY-PRODUCING CELLS.
Genes that cause the epigenotype (i.e., the interrelated developmental pathways through which the adult organism is realized) to switch to an alternate cell lineage-related pathway. Switch complexes control the expression of normal functional development as well as oncogenic transformation.
Ordered rearrangement of B-lymphocyte variable gene regions of the IMMUNOGLOBULIN HEAVY CHAINS, thereby contributing to antibody diversity. It occurs during the first stage of differentiation of the IMMATURE B-LYMPHOCYTES.
The orderly segregation of CHROMOSOMES during MEIOSIS or MITOSIS.
Viruses whose hosts are bacterial cells.
Either of the two longitudinally adjacent threads formed when a eukaryotic chromosome replicates prior to mitosis. The chromatids are held together at the centromere. Sister chromatids are derived from the same chromosome. (Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)
The domains of the immunoglobulin molecules that are invariable in their amino acid sequence within any class or subclass of immunoglobulin. They confer biological as well as structural functions to immunoglobulins. One each on both the light chains and the heavy chains comprises the C-terminus half of the IMMUNOGLOBULIN FAB FRAGMENT and two or three of them make up the rest of the heavy chains (all of the IMMUNOGLOBULIN FC FRAGMENT)
Fungal genes that mostly encode TRANSCRIPTION FACTORS. In some FUNGI they also encode PHEROMONES and PHEROMONE RECEPTORS. The transcription factors control expression of specific proteins that give a cell its mating identity. Opposite mating type identities are required for mating.
The relative amounts of the PURINES and PYRIMIDINES in a nucleic acid.
The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.
The complete gene complement contained in a set of chromosomes in a fungus.
An individual in which both alleles at a given locus are identical.
The genetic complement of a BACTERIA as represented in its DNA.
DNA TOPOISOMERASES that catalyze ATP-independent breakage of one of the two strands of DNA, passage of the unbroken strand through the break, and rejoining of the broken strand. DNA Topoisomerases, Type I enzymes reduce the topological stress in the DNA structure by relaxing the superhelical turns and knotted rings in the DNA helix.
Proteins encoded by homeobox genes (GENES, HOMEOBOX) that exhibit structural similarity to certain prokaryotic and eukaryotic DNA-binding proteins. Homeodomain proteins are involved in the control of gene expression during morphogenesis and development (GENE EXPRESSION REGULATION, DEVELOPMENTAL).
A programmed mutation process whereby changes are introduced to the nucleotide sequence of immunoglobulin gene DNA during development.
A type of chromosome aberration characterized by CHROMOSOME BREAKAGE and transfer of the broken-off portion to another location, often to a different chromosome.
Complex nucleoprotein structures which contain the genomic DNA and are part of the CELL NUCLEUS of MAMMALS.
The clear constricted portion of the chromosome at which the chromatids are joined and by which the chromosome is attached to the spindle during cell division.
A species of fruit fly much used in genetics because of the large size of its chromosomes.
Heavy chains of IMMUNOGLOBULIN G having a molecular weight of approximately 51 kDa. They contain about 450 amino acid residues arranged in four domains and an oligosaccharide component covalently bound to the Fc fragment constant region. The gamma heavy chain subclasses (for example, gamma 1, gamma 2a, and gamma 2b) of the IMMUNOGLOBULIN G isotype subclasses (IgG1, IgG2A, and IgG2B) resemble each other more closely than the heavy chains of the other IMMUNOGLOBULIN ISOTYPES.
Variation occurring within a species in the presence or length of DNA fragment generated by a specific endonuclease at a specific site in the genome. Such variations are generated by mutations that create or abolish recognition sites for these enzymes or change the length of the fragment.
Male germ cells derived from SPERMATOGONIA. The euploid primary spermatocytes undergo MEIOSIS and give rise to the haploid secondary spermatocytes which in turn give rise to SPERMATIDS.
The prophase of the first division of MEIOSIS (in which homologous CHROMOSOME SEGREGATION occurs). It is divided into five stages: leptonema, zygonema, PACHYNEMA, diplonema, and diakinesis.
DNA constructs that are composed of, at least, a REPLICATION ORIGIN, for successful replication, propagation to and maintenance as an extra chromosome in bacteria. In addition, they can carry large amounts (about 200 kilobases) of other sequence for a variety of bioengineering purposes.
The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.
Laboratory mice that have been produced from a genetically manipulated EGG or EMBRYO, MAMMALIAN.
Penetrating, high-energy electromagnetic radiation emitted from atomic nuclei during NUCLEAR DECAY. The range of wavelengths of emitted radiation is between 0.1 - 100 pm which overlaps the shorter, more energetic hard X-RAYS wavelengths. The distinction between gamma rays and X-rays is based on their radiation source.
A variety of simple repeat sequences that are distributed throughout the GENOME. They are characterized by a short repeat unit of 2-8 basepairs that is repeated up to 100 times. They are also known as short tandem repeats (STRs).
The first phase of cell nucleus division, in which the CHROMOSOMES become visible, the CELL NUCLEUS starts to lose its identity, the SPINDLE APPARATUS appears, and the CENTRIOLES migrate toward opposite poles.
A serine-threonine protein kinase that, when activated by DNA, phosphorylates several DNA-binding protein substrates including the TUMOR SUPPRESSOR PROTEIN P53 and a variety of TRANSCRIPTION FACTORS.
The parts of a macromolecule that directly participate in its specific combination with another molecule.
Ordered rearrangement of B-lymphocyte variable gene regions coding for the kappa or lambda IMMUNOGLOBULIN LIGHT CHAINS, thereby contributing to antibody diversity. It occurs during the second stage of differentiation of the IMMATURE B-LYMPHOCYTES.
Mapping of the linear order of genes on a chromosome with units indicating their distances by using methods other than genetic recombination. These methods include nucleotide sequencing, overlapping deletions in polytene chromosomes, and electron micrography of heteroduplex DNA. (From King & Stansfield, A Dictionary of Genetics, 5th ed)
One of the types of light chains of the immunoglobulins with a molecular weight of approximately 22 kDa.
The homologous chromosomes that are dissimilar in the heterogametic sex. There are the X CHROMOSOME, the Y CHROMOSOME, and the W, Z chromosomes (in animals in which the female is the heterogametic sex (the silkworm moth Bombyx mori, for example)). In such cases the W chromosome is the female-determining and the male is ZZ. (From King & Stansfield, A Dictionary of Genetics, 4th ed)
The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.
The phenomenon by which a temperate phage incorporates itself into the DNA of a bacterial host, establishing a kind of symbiotic relation between PROPHAGE and bacterium which results in the perpetuation of the prophage in all the descendants of the bacterium. Upon induction (VIRUS ACTIVATION) by various agents, such as ultraviolet radiation, the phage is released, which then becomes virulent and lyses the bacterium.
Viruses whose host is Escherichia coli.
The complete genetic complement contained in the DNA of a set of CHROMOSOMES in a HUMAN. The length of the human genome is about 3 billion base pairs.
A 15 kD "joining" peptide that forms one of the linkages between monomers of IMMUNOGLOBULIN A or IMMUNOGLOBULIN M in the formation of polymeric immunoglobulins. There is one J chain per one IgA dimer or one IgM pentamer. It is also involved in binding the polymeric immunoglobulins to POLYMERIC IMMUNOGLOBULIN RECEPTOR which is necessary for their transcytosis to the lumen. It is distinguished from the IMMUNOGLOBULIN JOINING REGION which is part of the IMMUNOGLOBULIN VARIABLE REGION of the immunoglobulin light and heavy chains.
Deoxyribonucleic acid that makes up the genetic material of plants.
Strains of mice in which certain GENES of their GENOMES have been disrupted, or "knocked-out". To produce knockouts, using RECOMBINANT DNA technology, the normal DNA sequence of the gene being studied is altered to prevent synthesis of a normal gene product. Cloned cells in which this DNA alteration is successful are then injected into mouse EMBRYOS to produce chimeric mice. The chimeric mice are then bred to yield a strain in which all the cells of the mouse contain the disrupted gene. Knockout mice are used as EXPERIMENTAL ANIMAL MODELS for diseases (DISEASE MODELS, ANIMAL) and to clarify the functions of the genes.
Genes that are introduced into an organism using GENE TRANSFER TECHNIQUES.
The uptake of naked or purified DNA by CELLS, usually meaning the process as it occurs in eukaryotic cells. It is analogous to bacterial transformation (TRANSFORMATION, BACTERIAL) and both are routinely employed in GENE TRANSFER TECHNIQUES.
The total relative probability, expressed on a logarithmic scale, that a linkage relationship exists among selected loci. Lod is an acronym for "logarithmic odds."
The genetic complement of a plant (PLANTS) as represented in its DNA.
Very long DNA molecules and associated proteins, HISTONES, and non-histone chromosomal proteins (CHROMOSOMAL PROTEINS, NON-HISTONE). Normally 46 chromosomes, including two sex chromosomes are found in the nucleus of human cells. They carry the hereditary information of the individual.
Specific regions that are mapped within a GENOME. Genetic loci are usually identified with a shorthand notation that indicates the chromosome number and the position of a specific band along the P or Q arm of the chromosome where they are found. For example the locus 6p21 is found within band 21 of the P-arm of CHROMOSOME 6. Many well known genetic loci are also known by common names that are associated with a genetic function or HEREDITARY DISEASE.

Different regulation of the p53 core domain activities 3'-to-5' exonuclease and sequence-specific DNA binding. (1/18933)

In this study we further characterized the 3'-5' exonuclease activity intrinsic to wild-type p53. We showed that this activity, like sequence-specific DNA binding, is mediated by the p53 core domain. Truncation of the C-terminal 30 amino acids of the p53 molecule enhanced the p53 exonuclease activity by at least 10-fold, indicating that this activity, like sequence-specific DNA binding, is negatively regulated by the C-terminal basic regulatory domain of p53. However, treatments which activated sequence-specific DNA binding of p53, like binding of the monoclonal antibody PAb421, which recognizes a C-terminal epitope on p53, or a higher phosphorylation status, strongly inhibited the p53 exonuclease activity. This suggests that at least on full-length p53, sequence-specific DNA binding and exonuclease activities are subject to different and seemingly opposing regulatory mechanisms. Following up the recent discovery in our laboratory that p53 recognizes and binds with high affinity to three-stranded DNA substrates mimicking early recombination intermediates (C. Dudenhoeffer, G. Rohaly, K. Will, W. Deppert, and L. Wiesmueller, Mol. Cell. Biol. 18:5332-5342), we asked whether such substrates might be degraded by the p53 exonuclease. Addition of Mg2+ ions to the binding assay indeed started the p53 exonuclease and promoted rapid degradation of the bound, but not of the unbound, substrate, indicating that specifically recognized targets can be subjected to exonucleolytic degradation by p53 under defined conditions.  (+info)

Evolutionary relationships of pathogenic clones of Vibrio cholerae by sequence analysis of four housekeeping genes. (2/18933)

Studies of the Vibrio cholerae population, using molecular typing techniques, have shown the existence of several pathogenic clones, mainly sixth-pandemic, seventh-pandemic, and U.S. Gulf Coast clones. However, the relationship of the pathogenic clones to environmental V. cholerae isolates remains unclear. A previous study to determine the phylogeny of V. cholerae by sequencing the asd (aspartate semialdehyde dehydrogenase) gene of V. cholerae showed that the sixth-pandemic, seventh-pandemic, and U.S. Gulf Coast clones had very different asd sequences which fell into separate lineages in the V. cholerae population. As gene trees drawn from a single gene may not reflect the true topology of the population, we sequenced the mdh (malate dehydrogenase) and hlyA (hemolysin A) genes from representatives of environmental and clinical isolates of V. cholerae and found that the mdh and hlyA sequences from the three pathogenic clones were identical, except for the previously reported 11-bp deletion in hlyA in the sixth-pandemic clone. Identical sequences were obtained, despite average nucleotide differences in the mdh and hlyA genes of 1.52 and 3.25%, respectively, among all the isolates, suggesting that the three pathogenic clones are closely related. To extend these observations, segments of the recA and dnaE genes were sequenced from a selection of the pathogenic isolates, where the sequences were either identical or substantially different between the clones. The results show that the three pathogenic clones are very closely related and that there has been a high level of recombination in their evolution.  (+info)

Insertion of excised IgH switch sequences causes overexpression of cyclin D1 in a myeloma tumor cell. (3/18933)

Oncogenes are often dysregulated in B cell tumors as a result of a reciprocal translocation involving an immunoglobulin locus. The translocations are caused by errors in two developmentally regulated DNA recombination processes: V(D)J and IgH switch recombination. Both processes share the property of joining discontinuous sequences from one chromosome and releasing intervening sequences as circles that are lost from progeny cells. Here we show that these intervening sequences may instead insert in the genome and that during productive IgH mu-epsilon switch recombination in U266 myeloma tumor cells, a portion of the excised IgH switch intervening sequences containing the 3' alpha-1 enhancer has inserted on chromosome 11q13, resulting in overexpression of the adjacent cyclin D1 oncogene.  (+info)

The L1 major capsid protein of human papillomavirus type 11 recombinant virus-like particles interacts with heparin and cell-surface glycosaminoglycans on human keratinocytes. (4/18933)

The L1 major capsid protein of human papillomavirus (HPV) type 11, a 55-kDa polypeptide, forms particulate structures resembling native virus with an average particle diameter of 50-60 nm when expressed in the yeast Saccharomyces cerevisiae. We show in this report that these virus-like particles (VLPs) interact with heparin and with cell-surface glycosaminoglycans (GAGs) resembling heparin on keratinocytes and Chinese hamster ovary cells. The binding of VLPs to heparin is shown to exhibit an affinity comparable to that of other identified heparin-binding proteins. Immobilized heparin chromatography and surface plasmon resonance were used to show that this interaction can be specifically inhibited by free heparin and dextran sulfate and that the effectiveness of the inhibitor is related to its molecular weight and charge density. Sequence comparison of nine human L1 types revealed a conserved region of the carboxyl terminus containing clustered basic amino acids that bear resemblance to proposed heparin-binding motifs in unrelated proteins. Specific enzymatic cleavage of this region eliminated binding to both immobilized heparin and human keratinocyte (HaCaT) cells. Removal of heparan sulfate GAGs on keratinocytes by treatment with heparinase or heparitinase resulted in an 80-90% reduction of VLP binding, whereas treatment of cells with laminin, a substrate for alpha6 integrin receptors, provided minimal inhibition. Cells treated with chlorate or substituted beta-D-xylosides, resulting in undersulfation or secretion of GAG chains, also showed a reduced affinity for VLPs. Similarly, binding of VLPs to a Chinese hamster ovary cell mutant deficient in GAG synthesis was shown to be only 10% that observed for wild type cells. This report establishes for the first time that the carboxyl-terminal portion of HPV L1 interacts with heparin, and that this region appears to be crucial for interaction with the cell surface.  (+info)

Viral gene delivery selectively restores feeding and prevents lethality of dopamine-deficient mice. (5/18933)

Dopamine-deficient mice (DA-/- ), lacking tyrosine hydroxylase (TH) in dopaminergic neurons, become hypoactive and aphagic and die by 4 weeks of age. They are rescued by daily treatment with L-3,4-dihydroxyphenylalanine (L-DOPA); each dose restores dopamine (DA) and feeding for less than 24 hr. Recombinant adeno-associated viruses expressing human TH or GTP cyclohydrolase 1 (GTPCH1) were injected into the striatum of DA-/- mice. Bilateral coinjection of both viruses restored feeding behavior for several months. However, locomotor activity and coordination were partially improved. A virus expressing only TH was less effective, and one expressing GTPCH1 alone was ineffective. TH immunoreactivity and DA were detected in the ventral striatum and adjacent posterior regions of rescued mice, suggesting that these regions mediate a critical DA-dependent aspect of feeding behavior.  (+info)

Locus specificity of polymorphic alleles and evolution by a birth-and-death process in mammalian MHC genes. (6/18933)

We have conducted an extensive phylogenetic analysis of polymorphic alleles from human and mouse major histocompatibility complex (MHC) class I and class II genes. The phylogenetic tree obtained for 212 complete human class I allele sequences (HLA-A, -B, and -C) has shown that all alleles from the same locus form a single cluster, which is highly supported by bootstrap values, except for one HLA-B allele (HLA-B*7301). Mouse MHC class I loci did not show locus-specific clusters of polymorphic alleles. This was considered to be because of either interlocus genetic exchange or the confusing designation of loci in different haplotypes at the present time. The locus specificity of polymorphic alleles was also observed in human and mouse MHC class II loci. It was therefore concluded that interlocus recombination or gene conversion is not very important for generating MHC diversity, with a possible exception of mouse class I loci. According to the phylogenetic trees of complete coding sequences, we classified human MHC class I (HLA-A, -B, and -C) and class II (DRB1) alleles into three to five major allelic lineages (groups), which were monophyletic with high bootstrap values. Most of these allelic groups remained unchanged even in phylogenetic trees based on individual exons, though this does not exclude the possibility of intralocus recombination involving short DNA segments. These results, together with the previous observation that MHC loci are subject to frequent duplication and deletion, as well as to balancing selection, indicate that MHC evolution in mammals is in agreement with the birth-and-death model of evolution, rather than with the model of concerted evolution.  (+info)

Mitotic recombination in the heterochromatin of the sex chromosomes of Drosophila melanogaster. (7/18933)

The frequency of spontaneous and X-ray-induced mitotic recombination involving the Y chromosome has been studied in individuals with a marked Y chromosome arm and different XY compound chromosomes. The genotypes used include X chromosomes with different amounts of X heterochromatin and either or both arms of the Y chromosome attached to either side of the centromere. Individuals with two Y chromosomes have also been studied. The results show that the bulk of mitotic recombination takes place between homologous regions.  (+info)

The prokaryotic beta-recombinase catalyzes site-specific recombination in mammalian cells. (8/18933)

The development of new strategies for the in vivo modification of eukaryotic genomes has become an important objective of current research. Site-specific recombination has proven useful, as it allows controlled manipulation of murine, plant, and yeast genomes. Here we provide the first evidence that the prokaryotic site-specific recombinase (beta-recombinase), which catalyzes only intramolecular recombination, is active in eukaryotic environments. beta-Recombinase, encoded by the beta gene of the Gram-positive broad host range plasmid pSM19035, has been functionally expressed in eukaryotic cell lines, demonstrating high avidity for the nuclear compartment and forming a clear speckled pattern when assayed by indirect immunofluorescence. In simian COS-1 cells, transient beta-recombinase expression promoted deletion of a DNA fragment lying between two directly oriented specific recognition/crossing over sequences (six sites) located as an extrachromosomal DNA substrate. The same result was obtained in a recombination-dependent lacZ activation system tested in a cell line that stably expresses the beta-recombinase protein. In stable NIH/3T3 clones bearing different number of copies of the target sequences integrated at distinct chromosomal locations, transient beta-recombinase expression also promoted deletion of the intervening DNA, independently of the insertion position of the target sequences. The utility of this new recombination tool for the manipulation of eukaryotic genomes, used either alone or in combination with the other recombination systems currently in use, is discussed.  (+info)

Recombination directionality factors (RDFs), or excisionases, are essential players of prophage excisive recombination. Despite the essentially catalytic role of the integrase in both integrative and excisive recombination, RDFs are required to direct the reaction towards excision and to prevent re-integration of the prophage genome when entering a lytic cycle. KplE1, HK620 and numerous (pro)phages that integrate at the same site in enterobacteria genomes (such as the argW tRNA gene) all share a highly conserved recombination module. This module comprises the attL and attR recombination sites and the RDF and integrase genes. The KplE1 RDF was named TorI after its initial identification as a negative regulator of the tor operon. However, it was characterized as an essential factor of excisive recombination. In this study, we designed an extensive random mutagenesis protocol of the torI gene and identified key residues involved in both functions of the TorI protein. We show that, in addition to TorI-TorR
Meiosis is a cell division process that produces haploid gametes from diploid cells. Several important meiotic events take place during prophase of meiosis I, most important being homologous chromosome pairing, meiotic recombination and formation of the synaptonemal complex (SC). These processes assure proper segregation of the homologous chromosomes into the haploid germ cells. Improper segregation of the homologos can cause chromosomal abnormality (aneuploidy), which causes various human disorders, notably mental retardation and pregnancy loss.. This thesis focuses on the relationship between recombination and the formation of SCs, aggregates of SC-related materials (polycomplexes) and recombination enzymes during meiosis. We have investigated SC formation in the absence of recombination, nature of polycomplexes and recombination enzymes in relation to the SCs structures and recombination nodules (RNs) in yeast Saccharomyces cerevisiae.. Studies on yeast mutants suggest that the formation of ...
To further establish the unusually high recombination rates of imprinted regions, it is informative to ask whether these have higher recombination rates than their flanking sequences. Of 16 bins containing an imprint, 3 have a sex-averaged recombination rate lower than the mean of the 3 flanking bins on either side, while 13 have a higher rate (P = 0.011, sign test; similar results are obtained for comparisons to the 5 or 10 flanking bins on either side). To examine the magnitude of this difference, we considered the difference in the recombination rate for every autosomal 1-Mb bin and the mean of the 3 flanking bins on either side. We then compared the data for imprinted bins with that of the genome as a whole. The sex-averaged recombination rate is higher than that predicted from the flanking blocks (Mann-Whitney U-test, P = 0.0074).. Thus, we report that for 13 of 16 imprinted regions the rate of recombination is higher in female meiosis compared to male meiosis, strongly suggesting that ...
60125DNAUnknownDescription of Unknown Recombination products oligonucleotide sequence 1rkycwgcttt yktrtacnaa stsgb 25225DNAUnknownDescription of Unknown Recombination products oligonucleotide sequence 2agccwgcttt yktrtacnaa ctsgb 25325DNAUnknownDescription of Unknown Recombination products oligonucleotide sequence 3gttcagcttt cktrtacnaa ctsgb 25425DNAUnknownDescription of Unknown Recombination products oligonucleotide sequence 4agccwgcttt cktrtacnaa gtsgb 25525DNAUnknownDescription of Unknown Recombination products oligonucleotide sequence 5gttcagcttt yktrtacnaa gtsgb 25625DNAUnknownDescription of Unknown Recombination products oligonucleotide sequence 6agcctgcttt tttgtacaaa cttgt 25725DNAUnknownDescription of Unknown Recombination products oligonucleotide sequence 7agcctgcttt cttgtacaaa cttgt 25825DNAUnknownDescription of Unknown Recombination products oligonucleotide sequence 8acccagcttt cttgtacaaa gtggt 25925DNAUnknownDescription of Unknown Recombination products oligonucleotide sequence ...
In the nematode Caenorhabditis elegans, recombination suppression in translocation heterozygotes is severe and extensive. We have examined the meiotic properties of two translocations involving chromosome I, szT1(I;X) and hT1(I;V). No recombination was observed in either of these translocation heterozygotes along the left (let-362-unc-13) 17 map units of chromosome I. Using half-translocations as free duplications, we mapped the breakpoints of szT1 and hT1. The boundaries of crossover suppression coincided with the physical breakpoints. We propose that DNA sequences at the right end of chromosome I facilitate pairing and recombination. We use the data from translocations of other chromosomes to map the location of pairing sites on four other chromosomes. hT1 and szT1 differed markedly in their effect on recombination adjacent to the crossover suppressed region. hT1 had no effect on recombination in the adjacent interval. In contrast, the 0.8 map unit interval immediately adjacent to the ...
Author Summary Homologous recombination is an indispensable feature of the mammalian meiotic program and an important mechanism for creating genetic diversity. Despite its central significance, recombination rates vary markedly between species and among individuals. Although recent studies have begun to unravel the genetic basis of recombination rate variation within populations, the genetic mechanisms of species divergence in recombination rate remain poorly characterized. In this study, we show that two closely related house mouse subspecies differ in their genomic recombination rates by ∼30%, providing an excellent model system for studying evolutionary divergence in this trait. Using quantitative genetic methods, we identify eight genomic regions that contribute to divergence in global recombination rate between these subspecies, including large effect loci and multiple loci on the X-chromosome. Our study uncovers novel genomic loci contributing to species divergence in global recombination rate
In Saccharomyces cerevisiae, Rad59 is required for multiple homologous recombination mechanisms and viability in DNA replication-defective rad27 mutant cells. Recently, four rad59 missense alleles were found to have distinct effects on homologous recombination that are consistent with separation-of-function mutations. The rad59-K166A allele alters an amino acid in a conserved α-helical domain, and, like the rad59 null allele diminishes association of Rad52 with double-strand breaks. The rad59-K174A and rad59-F180A alleles alter amino acids in the same domain and have genetically similar effects on homologous recombination. The rad59-Y92A allele alters a conserved amino acid in a separate domain, has genetically distinct effects on homologous recombination, and does not diminish association of Rad52 with double-strand breaks. In this study, rad59 mutant strains were crossed with a rad27 null mutant to examine the effects of the rad59 alleles on the link between viability, growth and the stimulation of
View Notes - Bacterial Recombination from MCB 2000 at University of Florida. BACTERIAL RECOMBINATION Purposes A. Vaccine production (subunit type) B. Production of proteins (growth hormone) C.
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To create this landmark map, Comeron and colleagues generated recombinant advanced intercross lines (RAIL), derived from eight crosses among twelve wild-derived lines. To accurately identify crossover and noncrossover events, haplotype rather than genotype data are required, and Comeron and colleagues use a clever technique to recover haplotypes. RAIL females were individually crossed to D. simulans, and the genomes of single hybrid progeny were sequenced with Illumina technology. Reads mapping to D. simulans were removed bioinformatically to reveal a haploid, meiotically produced D. melanogaster genome. In all, over 100,000 recombination events were localized with kilobase-level precision.. Certainly, this genome-wide recombination map will empower population genetic and molecular evolutionary studies in Drosophila for years to come. However, the sheer number of events catalogued combined with the resolution at which breakpoints could be mapped facilitates a great deal more than quantifying ...
Recombination increases dramatically during meiosis to promote genetic exchange and generate recombinant progeny. Interestingly, meiotic recombination is unevenly distributed throughout genomes, and, as a consequence, genetic and physical map distances do not have a simple linear relationship. Recombination hotspots and coldspots have been described in many organisms and often reflect global features of chromosome structure. In particular, recombination frequencies are often distorted within or outside sex-determining regions of the genome. Here, we report that recombination is elevated adjacent to the mating-type locus (MAT) in the pathogenic basidiomycete Cryptococcus neoformans. Among fungi, C. neoformans has an unusually large MAT locus, and recombination is suppressed between the two |100-kilobase mating-type specific alleles. When genetic markers were introduced at defined physical distances from MAT, we found the meiotic recombination frequency to be ~20% between MAT and a flanking marker at 5,
Recombination hotspots are regions in a genome that exhibit elevated rates of recombination relative to a neutral expectation. The recombination rate within hotspots can be hundreds of times that of the surrounding region. Recombination hotspots result from higher DNA break formation in these regions, and apply to both mitotic and meiotic cells. This appellation can refer to recombination events resulting from the uneven distribution of programmed meiotic double-strand breaks. Meiotic recombination through crossing over is thought to be a mechanism by which a cell promotes correct segregation of homologous chromosomes and repair of DNA damages. Crossing over requires a DNA double-stranded break followed by strand invasion of the homolog and subsequent repair. Initiation sites for recombination are usually identified by mapping crossing over events through pedigree analysis or through analysis of linkage disequilibrium. Linkage disequilibrium has identified more than 30,000 hotspots within the ...
Crossover generated by meiotic recombination is a fundamental event that facilitates meiosis and sexual reproduction. Comparative studies have shown wide variation in recombination rate among species, but the characterization of recombination features between cattle breeds has not yet been performed. Cattle populations in North America count millions, and the dairy industry has genotyped millions of individuals with pedigree information that provide a unique opportunity to study breed-level variations in recombination. Based on large pedigrees of Jersey, Ayrshire and Brown Swiss cattle with genotype data, we identified over 3.4 million maternal and paternal crossover events from 161,309 three-generation families. We constructed six breed- and sex-specific genome-wide recombination maps using 58,982 autosomal SNPs for two sexes in the three dairy cattle breeds. A comparative analysis of the six recombination maps revealed similar global recombination patterns between cattle breeds but with significant
Accessory replicative helicases aid the primary replicative helicase in duplicating protein-bound DNA, especially transcribed DNA. Recombination enzymes also aid genome duplication by facilitating the repair of DNA lesions via strand exchange and also processing of blocked fork DNA to generate structures onto which the replisome can be reloaded. There is significant interplay between accessory helicases and recombination enzymes in both bacteria and lower eukaryotes but how these replication repair systems interact to ensure efficient genome duplication remains unclear. Here, we demonstrate that the DNA content defects of Escherichia coli cells lacking the strand exchange protein RecA are driven primarily by conflicts between replication and transcription, as is the case in cells lacking the accessory helicase Rep. However, in contrast to Rep, neither RecA nor RecBCD, the helicase/exonuclease that loads RecA onto dsDNA ends, is important for maintaining rapid chromosome duplication. Furthermore, RecA
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We have characterized homologous recombination between linear DNA and the bacterial chromosome that depends on λ recombination functions, involves very short homologies, and is very efficient. We examined several parameters to establish a maximal efficiency for phage-mediated recombination with short homologies. Maximal recombination levels are achieved with induction times from 7.5-17.5 min at 42°C, and a homology segment of 40-50 bp. Recombination saturates at a linear DNA substrate concentration of about 300 molecules per cell.. The fact that 30- to 50-bp homologies are able to recombine in vivo opens a vast array of new possibilities for generating recombinant DNA. Several steps normally involved in generating recombinant DNA molecules are eliminated. Restriction enzyme digests are not required to generate DNA fragments, and DNA ligase reactions are not required to join different DNA fragments at novel junctions. PCR amplification followed by electroporation of the linear DNA into cells is ...
October 3, 2004. October 3, 2004 - In a paper published today in the online edition of Nature Genetics, a deCODE-led team of scientists present the results of a large-scale population study linking recombination rate with maternal age and fertility. In the paper, entitled Recombination rate and reproductive success in humans, the deCODE team establish a novel and significant correlation between recombination - the shuffling of chromosomal material that takes place in the formation of eggs and sperm - and maternal age and fertility. Specifically, the average number of recombinations in eggs that go on to become successful live births tends to increase with the mothers age, and mothers with a higher recombination rate in general also tend to have more children than do those with a lower recombination rate. The authors conclude that the most likely explanation for this phenomenon is that recombination, which is one of the most important mechanisms for generating genetic diversity in ...
Rates of intragenic recombination are suppressed in the vicinity of Ds and Mu1 insertions (23, 34, 40). In addition, Ds insertions are thought to alter the distribution of recombination breakpoints in the otherwise uniformly recombinogenic bz1 locus to create allele-specific hot and cold spots (34). In contrast, a preliminary analysis did not provide any evidence that a Mu1 insertion in the a1 gene alters the distribution of recombination event (23).. In this previous study, the positions of 15 recombination events isolated from the a1-mum2/a1∷rdt heterozygote were physically mapped within the 1.2-kb interval of the a1 gene that is defined by the Mu1 and rdt transposon insertions. All but one of these recombination events resolved within a 377-bp recombination hot spot. Xu et al. (23) compared this distribution of recombination events to those isolated from a directly comparable heterozygote that does not contain the Mu1 insertion in the a1 gene (A1-LC/a1∷rdt). This comparison is appropriate ...
TY - JOUR. T1 - ζ-/-thalassemic mice are affected by two modifying loci and display unanticipated somatic recombination leading to inherited variation. AU - Leder, Aya. AU - McMenamin, Jennifer. AU - Fontaine, Karen. AU - Bishop, Alexander. AU - Leder, Philip. PY - 2005/3/1. Y1 - 2005/3/1. N2 - Thalassemia is a disease caused by a variety of mutations affecting both the adult and embryonic α- and β-globin loci. A mouse strain carrying an embryonic ζ-globin gene disrupted by the insertion of a PGK-Neo cassette displays an α-thalassemia-like syndrome. Embryonic survival of this ζ-null mouse is variable and strongly influenced by genetic background, the 129/SvEv mouse strain displaying a more severe phenotype than C57BL/6. We have identified two modifying loci on C57BL/6 chromosomes 2 and 5, which affect the penetrance of embryonic lethality in the 129/SvEv mouse. Through this work, we were able to observe an interesting effect on somatic recombination events in thalassemic embryos. We show ...
The rapid spread of antimicrobial resistance and vaccine escape in the opportunistic human pathogen Streptococcus pneumoniae can be largely attributed to competence-induced transformation. To better understand why competence-induced transformation is so effective, we studied the dynamics of this process at the single-cell level. We show that within isogenic populations, all cells become naturally competent and bind exogenous DNA. In addition, we find that transformation is highly efficient and that the chromosomal location of the integration site or whether the transformed gene is encoded on the leading or lagging strand has limited influence on recombination efficiency. Indeed, we have observed multiple recombination events in single recipients in real-time. However, because of saturation of the DNA uptake and integration machinery and because a single stranded donor DNA replaces the original allele, we find that transformation efficiency has an upper threshold of approximately 50% of the population.
Sex and recombination are ubiquitous across the vast majority of life on earth. In eukaryotes, recombination during meiosis yields new variation that selection acts upon and, thus, facilitates evolution. However, meiosis provides an arena for manipulation and exploitation by selfish genetic elements. Selfish elements can increase in abundance independently of their host organism and frequently at a cost to host fitness. Several types of selfish elements act during meiosis and therefore it is possible for recombination rates and mechanisms to evolve to counteract and ameliorate their negative effects. However, few studies have investigated the interaction between recombination and selfish genetic elements. I conducted three studies on the evolution of recombination mechanisms in light of the impact of selfish elements. I begin my thesis with an introduction on selfish elements, recombination, and their possible interactions in Chapter 1. In Chapter 2, I found evidence that the synaptonemal ...
In viruses, recombination may allow foreign genes to be acquired or may create a composite genome through recombination between different virus variants. The ability to identify a recombinant virus and the positions where recombination occurred is only as certain as the identification of the component parental viral genomes from which it was generated. Recombination detection thus shares many elements and is ultimately dependent on evolutionary reconstructions and, most importantly, on methods for the delineation of separate phylogenetic groups. The structure of the 5 untranslated region (5 UTR) of picornaviruses provides a further example of modular exchange through recombination during the evolution of separate genera within the picornavirus family. Members of the same picornavirus genus show conserved gene order and content, and over the much shorter evolutionary time scale in which species and serotypes developed, gene exchange is best documented as homologous recombination events. One of the
Andrés Frankow. Genetic Recombination in Bacteria Horizon of the b. Uploaded by. Crispr methods for bacterial genome engineering. Homologous recombination has been most studied and is best understood for Escherichia coli. 1. an overview of bacterial recombination).The three main mechanisms by which bacteria acquire new DNA are transformation, conjugation, and transduction. 1. Introduction Deoxyribonucleic acid (DNA) damage is a common occurrence in all cells. Genetic recombination - transfer of DNA from one organism (donor) to another recipient. Many are downloadable. Saurav Suman. Bacteria Using Homologous Recombination 1.16.2 Supplement 78 Current Protocols in Molecular Biology of steps is a recombineering reaction that replaces the sequence to be modified with an antibiotic-resistance cassette and a counter-selectable marker (e.g., sacB, which is toxic when cells are grown on medium containing sucrose; Gay et al., 1985). Saurav Suman. Evolution of sexual reproduction is one of the major ...
Mutation and recombination are central processes driving microbial evolution. A high mutation rate fuels adaptation but also generates deleterious mutations. Recombination between two different genomes may resolve this paradox, alleviating effects of clonal interference and purging deleterious mutations. Here we demonstrate that recombination significantly accelerates adaptation and evolution during acute virus infection. We identified a poliovirus recombination determinant within the virus polymerase, mutation of which reduces recombination rates without altering replication fidelity. By generating a panel of variants with distinct mutation rates and recombination ability, we demonstrate that recombination is essential to enrich the population in beneficial mutations and purge it from deleterious mutations. The concerted activities of mutation and recombination are key to virus spread and virulence in infected animals. These findings inform a mathematical model to demonstrate that poliovirus ...
Meiotic recombination hotspots control the frequency and distribution of Spo11 (Rec12)-initiated recombination in the genome. Recombination occurs within and is regulated in part by chromatin structure, but relatively few of the many chromatin remodeling factors and histone posttranslational modifications (PTMs) have been interrogated for a role in the process. We developed a chromatin affinity purification and mass spectrometry-based approach to identify proteins and histone PTMs that regulate recombination hotspots. Small (4.2 kbp) minichromosomes (MiniCs) bearing the fission yeast ade6-M26 hotspot or a basal recombination control were purified approximately 100,000-fold under native conditions from meiosis; then, associated proteins and histone PTMs were identified by mass spectrometry. Proteins and PTMs enriched at the hotspot included known regulators (Atf1, Pcr1, Mst2, Snf22, H3K14ac), validating the approach. The abundance of individual histones varied dynamically during meiotic progression in
Genetic recombination is the production of offspring with combinations of traits that differ from those found in either parent. In eukaryotes, genetic recombination during meiosis can lead to a novel set of genetic information that can be passed on from the parents to the offspring. Most recombination is naturally occurring. During meiosis in eukaryotes, genetic recombination involves the pairing of homologous chromosomes. This may be followed by information transfer between the chromosomes. The information transfer may occur without physical exchange (a section of genetic material is copied from one chromosome to another, without the donating chromosome being changed) (see SDSA pathway in Figure); or by the breaking and rejoining of DNA strands, which forms new molecules of DNA (see DHJ pathway in Figure). Recombination may also occur during mitosis in eukaryotes where it ordinarily involves the two sister chromosomes formed after chromosomal replication. In this case, new combinations of ...
A direct test was made of predictions of the double-strand-break repair (DSBR) model of recombination in Xenopus laevis oocytes. The DNA substrate injected into oocytes had two directly repeated copies of a 1.25-kb sequence and was cleaved within one of them. Different products were expected to result from concerted, conservative events, as predicted by the DSBR model, and from nonconservative events. Only very low levels of recombination products, both conservative and nonconservative, were observed. When individual, apparent DSBR products were cloned and characterized, it emerged that the majority of them had arisen by nonconservative recombination through short, terminal homologies and not from the gene conversion events predicted for DSBR. Two cloned products among 44 tested corresponded to the predications of the DSBR model, but these could also have been generated by other processes. The most efficient recombination events in oocytes are nonconservative and are based on long, terminal ...
In yeast meiosis, ascosporal colonies are sometimes sectored for a marker--i.e., half the colony has one allele and half has the other. This is interpreted as replicative resolution of heteroduplex DNA (hDNA) formed as a recombination intermediate. We have looked for similar evidence of hDNA formation during mitotic recombination between two repeated sequences on the same chromosome. The two repeats, an ochre suppressor and a wild-type tRNA gene, are separated by plasmid DNA and the URA3 marker. Recombination between the repeats excises the URA3 gene and one copy of the repeat, leaving either the wild-type tRNA or the suppressor on the chromosome. A red/white color assay is used to distinguish between the two. We find that some colonies that have lost the URA3 gene are sectored for the suppressor. This suggests that hDNA is formed across the anticodon during the recombination event and then resolved by replication. The disruption of either of two genes involved in recombination and repair, RAD1 and
[email protected] research • lab members • publications. My lab is active in three somewhat related research areas: 1) the mechanism of mitotic recombination, 2) the genetic regulation of genome stability, and 3) genetic instability associated with interstitial telomeric sequences. Almost all of our studies are done using the yeast Saccharomyces cerevisiae.. Mechanism of mitotic recombination. Mitotic recombination, an important mechanism for the repair of DNA damage, is less well characterized than meiotic recombination. One difficulty is that mitotic recombination events are 104-fold less frequent than meiotic recombination events. We developed a greatly improved system for identifying and mapping mitotic crossovers at 1-kb resolution throughout the genome. This system uses DNA microarrays to detect loss of heterozygosity (LOH) resulting from mitotic crossovers. We identified motifs associated with high levels of spontaneous mitotic recombination. In particular, we demonstrated that a ...
The emergence of novel pathogenic organisms due to the acquisition of virulence determinants from bacteriophages has generated significant interest in the pathways responsible for genomic rearrangements. Phageλ encodes its own recombination system, the Red system, comprising Exo, β and γ proteins. In addition,λ encodes another recombinase, Orf, which participates in the initial stages of genetic exchange and supplies a frmction equivalent to that of the Escherichia coli RecFOR proteins. This thesis focuses on determining the function of Orf in phage and bacterial recombination pathways by analysing its impact on recombinases encoded by λ and E. coli. Experiments revealed that Orf interacts with bacterial and phage recombination proteins in the initial exchange step of recombination, modulating the activities of both Exo and RecA. Orf, along with β, attenuates the 5-3 exonuclease activity of Exo, a feature that depends largely on the ability of Orf to bind DNA. Orf also facilitates ...
Parasites and hosts are involved in a continuous coevolutionary process leading to genetic changes in both counterparts. To understand this process, it is necessary to track host responses, one of which could be an increase in sex and recombination, such as is proposed by the Red Queen hypothesis. In this theoretical framework, the inducible recombination hypothesis states that B-chromosomes (genome parasites that prosper in natural populations of many living beings) elicit an increase in host chiasma frequency that is favoured by natural selection because it increases the proportion of recombinant progeny, some of which could be resistant to both B-chromosome effects and B-accumulation in the germline. We have found a clear parallelism between host recombination and the evolutionary status of the B-chromosome polymorphism, which provides explicit evidence for inducible recombination and strong support for the Red Queen hypothesis.. ...
Despite their importance to successful meiosis and various evolutionary processes, meiotic recombination rates sometimes vary within species or between closely related species. For example, humans and chimpanzees share virtually no recombination hotspot locations in the surveyed portion of the genom …
Although DNA is surprisingly fluid, there are enzymes that mediate recombination--by initiating DNA binding, strand invasion, and stabilizing ssDNA intermediates. Also, of important note, is that organisms have varying degrees of recombination levels. A classical example occurs within the Mycobacteria. Mycobacterium smegmatis has relatively low levels of illegitimate recombination (IR), while M. tuberculosis is notorious for high levels of IR compared to homologous recombination. This raises a question that can be phrased in a few ways. What enzymes are responsible for IR? or perhaps, What enzymes for homologous recombination are lacking ...
Lien vers Pubmed [PMID] - 15218022. J. Biol. Chem. 2004 Aug;279(35):36625-32. By frequently rearranging large regions of the genome, genetic recombination is a major determinant in the plasticity of the human immunodeficiency virus type I (HIV-1) population. In retroviruses, recombination mostly occurs by template switching during reverse transcription. The generation of retroviral vectors provides a means to study this process after a single cycle of infection of cells in culture. Using HIV-1-derived vectors, we present here the first characterization and estimate of the strength of a recombination hot spot in HIV-1 in vivo. In the hot spot region, located within the C2 portion of the gp120 envelope gene, the rate of recombination is up to ten times higher than in the surrounding regions. The hot region corresponds to a previously identified RNA hairpin structure. Although recombination breakpoints in vivo cluster in the top portion of the hairpin, the bias for template switching in this same ...
Meiotic recombination is initiated by DNA double-strand breaks (DSBs) created by the topoisomerase-like protein Spo11. During DSB formation, Spo11 becomes covalently attached to the 5 DSB ends. Removal of Spo11 is essential to repair the DSB by homologous recombination. Spo11 is removed endonucleolytically creating short-lived Spo11-oligonucleotide products. Here I demonstrate that: 1. Spo11-oligonucleotide products are not detected in recombination mutants believed to be defective in meiotic DSB formation. 2. When DSB repair is delayed, Spo11-oligonucleotides persist for longer. 3. Processing of Spo11-DSB ends to create Spo11-oligonucleotides is largely dependent on Mec1 and Tel1 activity. In the process of investigating Spo11-oligonucleotide degradation, it was observed that a mutant defective in both the meiotic recombination checkpoint and in DSB repair failed to accumulate the expected level of DSBs. Work described here leads to the proposal of a DSB feedback mechanism that functions ...
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The complex correlation structure of a collection of orthologous DNA sequences is uniquely captured by the ancestral recombination graph (ARG), a complete record of coalescence and recombination events in the history of the sample. However, existing methods for ARG inference are computationally in …
BACKGROUND:Genetic recombination can produce heterogeneous phylogenetic histories within a set of homologous genes. These recombination events can be obscured by subsequent residue substitutions, which consequently complicate their detection. While there are many algorithms for the identification of recombination events, little is known about the effects of subsequent substitutions on the accuracy of available recombination-detection approaches.RESULTS:We assessed the effect of subsequent substitutions on the detection of simulated recombination events within sets of four nucleotide sequences under a homogeneous evolutionary model. The amount of subsequent substitutions per site, prior evolutionary history of the sequences, and reciprocality or non-reciprocality of the recombination event all affected the accuracy of the recombination-detecting programs examined. Bayesian phylogenetic-based approaches showed high accuracy in detecting evidence of recombination event and in identifying ...
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The coordinated rearrangement of antigen receptor gene segments during V(D)J recombination is dependent on a complex series of DNA-processing reactions (20, 30, 45). Essential to the initiation of the process are recombination signal sequences (RSSs), which consist of two conserved DNA recognition motifs, the heptamer (consensus, CACAGTG) and the nonamer (consensus, ACAAAAACC) (32). These motifs are separated by predominantly nonconserved spacer regions of either 12 or 23 bp. Effective recombination is achieved by the 12/23 rule, which limits rearrangement to gene segments flanked by RSSs with different spacer lengths (15, 55, 60).. Recombination-activating genes 1 and 2 (RAG1 and RAG2) encode the lymphoid cell-specific recombinase components (36, 46) that are central to the rearrangement process. Normally, the V(D)J recombination reaction proceeds with nonamer recognition mediated by a DNA binding region of RAG1 (nonamer binding domain) that displays homology to the DNA recognition domains of ...
Recombination raises during meiosis to market genetic exchange and generate recombinant progeny dramatically. hereditary markers were released at described physical ranges from we discovered the meiotic recombination rate of recurrence to become ~20% between and a flanking marker at 5, 10, 50, or 100 kilobases from the proper border. As a total result, the physical/hereditary map percentage in the areas adjacent to can be distorted ~10- to 50-collapse set alongside the genome-wide normal. Moreover, recombination frequently occurred on both family member edges of and bad disturbance between crossovers was observed. heterozygosity had not been required for improved recombination, implying that process CALNA2 isnt because of a physical distortion from both non-paired alleles and may also happen during same-sex mating. Series analysis exposed a 68550-75-4 supplier relationship between high G + C content material and these hotspot areas. We hypothesize that the current presence of recombinational ...
I have posted a few times before about a new group bionet.molbio.recombination that I will be proposing soon.... Here is the rough proposal... if you have any comments please send them!!!! Start----------- Proposal to establish RECOMBINATION/bionet.molbio.recombination Proposed USENET name: bionet.molbio.recombination (unmoderated) Proposed mailing list name: RECOMBINATION Proposed e-mail addresses: recom at recom at Discussion leaders: Graham Dellaire, e-mail: popa0206 at (b2xe at Department of Medicine (Div. of Exp. Medicine), McGill Univeristy, Montreal, Quebec, Canada George Szatmari, e-mail: szat at Tentatively Denis Cournoyer (Mcgill Experimental Medicine) (gene therapy) Terry Chow (McGill): e-mail MDTY at (mammalian genetics) Charter: The purpose of the RECOMBINATION newsgroup is to provide a proper forum for the discussion of issues pertaining and involving recombination of DNA or RNA, in its ...
In the budding yeast Saccharomyces cerevisiae, unnatural stabilization of the cyclin-dependent kinase inhibitor Sic1 during meiosis can trigger extra rounds of DNA replication. When programmed DNA double-strand breaks are generated but not repaired due to absence of DMC1, a pathway involving the checkpoint gene RAD17 prevents this DNA rereplication. Further genetic analysis has now revealed that prevention of DNA rereplication also requires MEC1, which encodes a protein kinase that serves as a central checkpoint regulator in several pathways including the meiotic recombination checkpoint response. Downstream of MEC1, MEK1 is required through its function to inhibit repair between sister chromatids. By contrast, meiotic recombination checkpoint effectors that regulate gene expression and cyclin-dependent kinase activity are not necessary. Phosphorylation of histone H2A, which is catalyzed by Mec1 and the related Tel1 protein kinase in response to DNA double-strand breaks and can help coordinate ...
TY - JOUR. T1 - Predicting knot and catenane type of products of site-specific recombination on twist knot substrates. AU - Valencia, Karin. AU - Buck, Dorothy. N1 - Copyright © 2011 Elsevier Ltd. All rights reserved.. PY - 2011/8/12. Y1 - 2011/8/12. N2 - Site-specific recombination on supercoiled circular DNA molecules can yield a variety of knots and catenanes. Twist knots are some of the most common conformations of these products, and they can act as substrates for further rounds of site-specific recombination. They are also one of the simplest families of knots and catenanes. Yet, our systematic understanding of their implication in DNA and important cellular processes such as site-specific recombination is very limited. Here, we present a topological model of site-specific recombination characterizing all possible products of this reaction on twist knot substrates, extending the previous work of Buck and Flapan. We illustrate how to use our model to examine previously uncharacterized ...
Homologous recombination plays a central role in the repair of double-strand DNA breaks, the restart of stalled replication forks and the generation of genetic diversity. Regulation of recombination is essential since defects can lead to genome instability and chromosomal rearrangements. Strand exchange is a key step of recombination - it is catalysed by RecA in bacteria, Rad51/Dmc1 in eukaryotes and RadA in archaea. RadB, a paralogue of RadA, is present in many archaeal species. RadB has previously been proposed to function as a recombination mediator, assisting in RadA-mediated strand exchange. In this study, we use the archaeon Haloferax volcanii to provide evidence to support this hypothesis. We show that RadB is required for efficient recombination and survival following treatment with DNA-damaging agents, and we identify two point mutations in radA that suppress the ΔradB phenotype. Analysis of these point mutations leads us to propose that the role of RadB is to act as a recombination ...
Looking for online definition of nonreciprocal recombination in the Medical Dictionary? nonreciprocal recombination explanation free. What is nonreciprocal recombination? Meaning of nonreciprocal recombination medical term. What does nonreciprocal recombination mean?
Looking for negative interference? Find out information about negative interference. A crossover exchange between homologous chromosomes which increases the likelihood of another in the same vicinity Explanation of negative interference
Cre-Lox recombination is a special type of site-specific recombination. The Cre protein is a site-specific DNA recombinase. It can catalyze the recombination of DNA between specific sites in a DNA molecule. These sites, known as loxP sequences, contain specific binding sites for Cre that surround a directional core sequence where recombination can occur. It is often used in the generation of knockout and conditional knockout animals. - Cre-Lox Recombination - AbVideo™ - Support - Abnova
Neale, Matt (2010) PRDM9 points the zinc finger at meiotic recombination hotspots. Genome Biology, 11 (2). p. 104. ISSN 14656914 Full text not available from this repository ...
Genetic investigations of malaria require a genome-wide, high-resolution linkage map of Plasmodium falciparum. A genetic cross was used to construct such a map from 901 markers that fall into 14 inferred linkage groups corresponding to the 14 nuclear chromosomes. Meiotic crossover activity in the genome proved high (17 kilobases per centimorgan) and notably uniform over chromosome length. Gene conversion events and spontaneous microsatellite length changes were evident in the inheritance data. The markers, map, and recombination parameters are facilitating genome sequence assembly, localization of determinants for such traits as virulence and drug resistance, and genetic studies of parasite field populations. ...
Understanding the influences of population structure, selection, and recombination on polymorphism and linkage disequilibrium (LD) is integral to mapping genes contributing to drug resistance or virulence in Plasmodium falciparum. The parasites short generation time, coupled with a high cross-over rate, can cause rapid LD break-down. However, observations of low genetic variation have led to suggestions of effective clonality: selfing, population admixture, and selection may preserve LD in populations. Indeed, extensive LD surrounding drug-resistant genes has been observed, indicating that recombination and selection play important roles in shaping recent parasite genome evolution. These studies, however, provide only limited information about haplotype variation at local scales. Here we describe the first (to our knowledge) chromosome-wide SNP haplotype and population recombination maps for a global collection of malaria parasites, including the 3D7 isolate, whose genome has been sequenced previously.
We used circularization-dependent and orientation-specific split scAAV vectors as a model system for the characterization of recombination between different DNA HP structures. This virus-based delivery system permitted controlled and quantifiable transport of DNA substrates to the nucleus. By taking advantage of the unique properties of the scAAV genome, we could control the orientation of the reporter gene segments between the open and closed TR HP ends. This, in turn, allowed the measurement and characterization of recombination events between different kinds of HP structures, represented by AAV termini. We observed that both the open and closed HP scAAV ends can serve as substrates for circularization and concatemerization. The two TR HP ends are not equivalent in recombination efficiency or sensitivity to drug inhibition. Indeed, it was surprising to discover that the joining of two closed HP ends was more efficient than any combination involving an open TR in concatemerization. However, ...
TY - JOUR. T1 - The relation between recombination rate and patterns of molecular evolution and variation in Drosophila melanogaster. AU - Campos, José L. AU - Halligan, Daniel L. AU - Haddrill, Penelope R. AU - Charlesworth, Brian. PY - 2014/4. Y1 - 2014/4. N2 - Genetic recombination associated with sexual reproduction increases the efficiency of natural selection by reducing the strength of Hill-Robertson interference. Such interference can be caused either by selective sweeps of positively selected alleles or by background selection (BGS) against deleterious mutations. Its consequences can be studied by comparing patterns of molecular evolution and variation in genomic regions with different rates of crossing over. We carried out a comprehensive study of the benefits of recombination in Drosophila melanogaster, both by contrasting five independent genomic regions that lack crossing over with the rest of the genome and by comparing regions with different rates of crossing over, using data on ...
High resolution analyses indicate that meiotic crossovers in human autosomes tend to cluster into 1-2 kb hotspots separated by blocks of high LD tens to hundreds of kilobases long. In contrast, low resolution data suggest only modest regional variation in recombination efficiency across the 2.6 Mb Xp/Yp pseudoautosomal region (PAR1), a male-specific recombination hot domain with a recombination rate about twenty times higher than the genome average. Recent data suggest a more complex picture of PAR1 recombination. Around the SHOX gene, 500 kb from the telomere, LD decays extremely rapidly with physical distance, but nearly all crossovers cluster into a highly localised hotspot about 2 kb wide. In contrast, SNPs in a 1.5 kb region immediately adjacent to the PAR1 telomere are in intense LD, implying that this region is recombinationally inert and that male crossover activity terminates at a currently unidentified boundary in the distal region of PAR1. To further investigate PAR1 recombination, ...
Author(s): Yin, Yi; Petes, Thomas D | Abstract: In the yeast Saccharomyces cerevisiae and most other eukaryotes, mitotic recombination is important for the repair of double-stranded DNA breaks (DSBs). Mitotic recombination between homologous chromosomes can result in loss of heterozygosity (LOH). In this study, LOH events induced by ultraviolet (UV) light are mapped throughout the genome to a resolution of about 1 kb using single-nucleotide polymorphism (SNP) microarrays. UV doses that have little effect on the viability of diploid cells stimulate crossovers more than 1000-fold in wild-type cells. In addition, UV stimulates recombination in G1-synchronized cells about 10-fold more efficiently than in G2-synchronized cells. Importantly, at high doses of UV, most conversion events reflect the repair of two sister chromatids that are broken at approximately the same position whereas at low doses, most conversion events reflect the repair of a single broken chromatid. Genome-wide mapping of about 380
Triple-negative breast cancers (TNBC) lack expression of estrogen and progesterone receptors and overexpression or amplification of the HER2/neu oncogene, and are therefore not amenable to therapy directed at these targets. Sporadic (BRCA1 and BRCA2 germline wild-type) TNBCs share many characteristics with BRCA1 mutation-associated cancers, including a basal-like gene expression profile, frequent p53 mutations, and a high burden of genomic aberrations such as loss of heterozygosity (1-7). BRCA1 or BRCA2 (BRCA1/2)-mutated cancers have defects in several aspects of DNA repair including homologous recombination deficiency (HRD; refs. 1, 8). BRCA1/2 mutation-associated cancers have been shown to have increased sensitivity to DNA crosslinking agents such as platinum salts (9). A number of studies have suggested that some sporadic TNBC may bear substantial similarities to BRCA1/2-mutated cancers, including harboring DNA repair defects that might predispose to platinum sensitivity (1, 10, 11). ...
1. RaddingCM 1981 Recombination activities of E. coli recA protein. Cell 25 3 4. 2. LusettiSLCoxMM 2002 The bacterial RecA protein and the recombinational DNA repair of stalled replication forks. Annu Rev Biochem 71 71 100. 3. CoxMM 2007 Regulation of bacterial RecA protein function. Crit Rev Biochem Mol Biol 42 41 63. 4. CoxMM 2007 Motoring along with the bacterial RecA protein. Nat Rev Mol Cell Biol 8 127 138. 5. TamasIKlassonLCanbackBNaslundAKErikssonAS 2002 50 million years of genomic stasis in endosymbiotic bacteria. Science 296 2376 2379. 6. SeitzEMBrockmanJPSandlerSJClarkAJKowalczykowskiSC 1998 RadA protein is an archaeal RecA protein homolog that catalyzes DNA strand exchange. Genes Dev 12 1248 1253. 7. ShinoharaAOgawaHOgawaT 1992 Rad51 protein involved in repair and recombination in S. cerevisiae is a RecA-like protein. Cell 69 457 470. 8. VamvakasSVockEHLutzWK 1997 On the role of DNA double-strand breaks in toxicity and carcinogenesis. Crit Rev Toxicol 27 155 174. 9. KhannaKKJacksonSP ...
Malaria parasites undergo a mainly haploid life-cycle. The only diploid stage is the zygote, formed by fusion of gametes in the mosquito stomach. The first division of the zygote is a meiotic one, producing, after further mitotic divisions, haploid sporozoites. Genetic recombination occurs at meiosis, following cross-fertilization of gametes of parasites with different genotypes. This has been shown in laboratory studies by feeding mosquitoes on a mixture of Plasmodium falciparum clones and analyzing the resulting progeny for parasites with non-parental combinations of the clone markers. Such recombinants are produced at a higher than expected frequency. There is considerable genotype diversity in field populations of P. falciparum. Evidence that recombination in mosquitoes is the principal cause of this diversity is two-fold. First, parasites isolated from patients in small isolated communities at the same time are genetically very diverse. No two isolates examined for polymorphic markers at ...
The tumor suppressor p53 is a transcription factor whose function is critical for maintaining genomic stability in mammalian cells. In response to DNA damage, p53 initiates a signaling cascade that results in cell cycle arrest, DNA repair or, if the damage is severe, programmed cell death. In addition, p53 interacts with repair proteins involved in homologous recombination. Mitotic homologous recombination (HR) plays an essential role in the repair of double-strand breaks (DSBs) and broken replication forks. Loss of function of either p53 or HR leads to an increased risk of cancer. Given the importance of both p53 and HR in maintaining genomic integrity, we analyzed the effect of p53 on HR in vivo using Fluorescent Yellow Direct Repeat (FYDR) mice as well as with the sister chromatid exchange (SCE) assay. FYDR mice carry a direct repeat substrate in which an HR event can yield a fluorescent phenotype. Here, we show that p53 status does not significantly affect spontaneous HR in adult pancreatic ...
Introduction of new antibiotic resistance genes in the plasmids of interest is a frequent task in molecular cloning practice. Classical approaches involving digestion with restriction endonucleases and ligation are time-consuming. We have created a set of insertion vectors (pINS) carrying genes that provide resistance to various antibiotics (puromycin, blasticidin and G418) and containing a loxP site. Each vector (pINS-Puro, pINS-Blast or pINS-Neo) contains either a chloramphenicol or a kanamycin resistance gene and is unable to replicate in most E. coli strains as it contains a conditional R6Kγ replication origin. Introduction of the antibiotic resistance genes into the vector of interest is achieved by Cre-mediated recombination between the replication-incompetent pINS and a replication-competent target vector. The recombination mix is then transformed into E. coli and selected by the resistance marker (kanamycin or chloramphenicol) present in pINS, which allows to recover the recombinant plasmids
Free-living bacteria are usually thought to have large effective population sizes, and so tiny selective differences can drive their evolution. However, because recombination is infrequent, background selection against slightly deleterious alleles should reduce the effective population size (N e) by orders of magnitude. For example, for a well-mixed population with 10 12 individuals and a typical level of homologous recombination (r/m= 3, i.e., nucleotide changes due to recombination [r] occur at 3 times the mutation rate [m]), we predict that N e is,10 7. An argument for high N e values for bacteria has been the high genetic diversity within many bacterial species, but this diversity may be due to population structure: diversity across subpopulations can be far higher than diversity within a subpopulation, which makes it difficult to estimate N e correctly. Given an estimate ofN e, standard population genetics models imply that selection should be sufficient to drive evolution if N e ×s is ...
V(D)J recombination is initiated by lymphoid-specific recombination activating gene 1 (RAG1) and RAG2 proteins, which introduce DSBs precisely between immunoglobulin and T cell receptor (TCR) coding gene segments and flanking recombination signal sequences. RAG-mediated cleavage generates four broken-end intermediates: two blunt signal ends and two covalently closed coding hairpin ends (1). The subsequent resolution of V(D)J ends into coding and signal joints requires ubiquitously expressed factors that function in general DSB repair (2,3). Although V(D)J recombination generates DNA damage, it has been presumed that broken DNA intermediates, which associate with RAG proteins within a postcleavage synaptic complex (4, 5), are sequestered from the DNA damage surveillance machinery. Primary DNA damage sensors include histone H2AX, which becomes rapidly phosphorylated (γ-H2AX) in response to external damage (6, 7), and the MRE11/RAD50/NBS1 complex, which forms ionizing irradiation-induced foci at ...
Recombination between homologous, but non-allelic, stretches of DNA such as gene families, segmental duplications and repeat elements is an important source of mutation. In humans, recent studies have identified short DNA motifs that both determine the location of 40 per cent of meiotic cross-over hotspots and are significantly enriched at the breakpoints of recurrent non-allelic homologous recombination (NAHR) syndromes. Unexpectedly, the most highly penetrant form of the motif occurs on the background of an inactive repeat element family (THE1 elements) and the motif also has strong recombinogenic activity on currently active element families including Alu and LINE2 elements. Analysis of genetic variation among members of these repeat families indicates an important role for NAHR in their evolution. Given the potential for double-strand breaks within repeat DNA to cause pathological rearrangement, the association between repeats and hotspots is surprising. Here we consider possible explanations for
DNA-skadande ämnen är vanligt i cancerbehandling, då snabbt växande celler, såsom cancerceller är betydligt känsligare än normala celler för DNA skador. En grupp av ämnen som vanligen används i cancerbehandling är korsbindare av DNA. Dessa ämnen kommer reagera två gånger med DNA och skapa två bindningar mitt emot varandra. DNA strängen, som består av två delar, måste kunna separeras och kopieras (replikation) på ett tillförlitligt sätt för att cellerna ska kunna dela sig och bli flera. DNA strängen måste också kunna dela sig och bli avläst rätt för att nya proteiner ska kunna bildas (transkription). När korsbindarna har bundit till DNA strängarna, hindrar detta deras separation och därigenom förhindras även avläsningen och kopieringen. För att göra undersökningarna av DNA korsbindande ämnen ännu lite svårare, så ger korsbindare flera olika typer av skador. Dels kan det bli flera olika typer av korsbindningar, både mellan två DNA-strängar (ICL) vilket ...
17. Katagiri, T., Saito, H., Shinohara, A., Ogawa, H., Kamada, N., Nakamura Y. and Y. Miki. Multiple possible sites of BRCA2 interacting with DNA repair protein Rad51. Genes, Chromosomes and Cancer, 21, 217-222. 1998, CI=43.. 18. Gasior, S., Wang, A., Kohra, Y., Shinohara, A. and D.K. Bishop. Rad52 associates with RPA and functions with Rad55 and Rad57 to assemble meiotic recombination complexes. Genes & Dev., 12, 2208-2221, 1998, CI=183.. 19. Bishop, D.K., Ear, U., Bhattacharyya, A., Calderone, C., Beckett, M., Weichselbaum, R. and A. Shinohara. Xrcc3 is required for assembly of Rad51-complexes in vivo. J. Biol. Chem., 273, 21482-21488. 1998, CI=213.. 20. Takata, M., Sasaki, M., Sonoda, E., Morrison, C., Hashimoto, M., Utsumi, H., Yamaguchi-Iwai, Y., Shinohara, A., and S. Takeda. Homologous recombination and non-homologous end-joining pathways of DNA double-strand break repair have overlapping roles in maintenance of chromosome integrity. EMBO J., 17, 5497-5508. 1998, CI=797.. 21. Nishitani, ...
Homologous recombination (HR) is involved in the creation of genetic diversity, maintenance of chromosome structure, and restoration of DNA damage. In mammals, efficient repair of double-strand breaks and interstrand crosslinks requires activities of Rad51 (a RecA homolog) and the Rad51-related proteins: Rad51B (Rad51L1), Rad51C (Rad51L2), Rad51D (Rad51L3), Xrcc2, Xrcc3, and Dmc1. RAD51 family genes demonstrate alternative splicing, and approximately 45% amino acid similarity is shared among their full-length translation products. All Rad51 proteins contain Walker box motifs consistent with an ability to bind and hydrolyze ATP. Two distinct complexes, Rad51B-Rad51C-Rad51D-Xrcc2 and Rad51C-Xrcc3, participate in early and late HR. With exception of Dmc1, deletions of the Rad51 genes in mouse are lethal; however, failure of Rad51d-null cells to proliferate can be overcome by disruption of the Trp53 tumor suppressor gene. Initial studies described in this dissertation ascertained that ...
The construction of a delivery and clearing system for the generation of food-grade recombinant lactic acid bacterium strains, based on the use of an integrase (Int) and a resolvo-invertase (β-recombinase) and their respective target sites (attP-attB and six, respectively) is reported. The delivery system contains a heterologous replication origin and antibiotic resistance markers surrounded by two directly oriented six sites, a multiple cloning site where passenger DNA could be inserted (e.g., the cI gene of bacteriophage A2), the int gene, and the attP site of phage A2. The clearing system provides a plasmid-borne gene encoding β-recombinase. The nonreplicative vector-borne delivery system was transformed into Lactobacillus casei ATCC 393 and, by site-specific recombination, integrated as a single copy in an orientation- and Int-dependent manner into the attB site present in the genome of the host strain. The transfer of the clearing system into this strain, with the subsequent expression of ...
UNLABELLED: Phylogenetic inference in bacterial genomics is fundamental to understanding problems such as population history, antimicrobial resistance, and transmission dynamics. The field has been plagued by an apparent state of contradiction since the distorting effects of recombination on phylogeny were discovered more than a decade ago. Researchers persist with detailed phylogenetic analyses while simultaneously acknowledging that recombination seriously misleads inference of population dynamics and selection. Here we resolve this paradox by showing that phylogenetic tree topologies based on whole genomes robustly reconstruct the clonal frame topology but that branch lengths are badly skewed. Surprisingly, removing recombining sites can exacerbate branch length distortion caused by recombination. IMPORTANCE: Phylogenetic tree reconstruction is a popular approach for understanding the relatedness of bacteria in a population from differences in their genome sequences. However, bacteria frequently
TY - JOUR. T1 - Nuclear dynamics of the Set1C subunit Spp1 prepares meiotic recombination sites for break formation. AU - Karányi, Zsolt. AU - Halász, László. AU - Acquaviva, Laurent. AU - Jónás, Dávid. AU - Hetey, Szabolcs. AU - Boros‑Oláh, Beáta. AU - Peng, Feng. AU - Chen, Doris. AU - Klein, Franz. AU - Géli, Vincent. AU - Székvölgyi, Lóránt. PY - 2018/10/1. Y1 - 2018/10/1. N2 - Spp1 is the H3K4me3 reader subunit of the Set1 complex (COMPASS/Set1C) that contributes to the mechanism by which meiotic DNA break sites are mechanistically selected. We previously proposed a model in which Spp1 interacts with H3K4me3 and the chromosome axis protein Mer2 that leads to DSB formation. Here we show that spatial interactions of Spp1 and Mer2 occur independently of Set1C. Spp1 exhibits dynamic chromatin binding features during meiosis, with many de novo appearing and disappearing binding sites. Spp1 chromatin binding dynamics depends on its PHD finger and Mer2-interacting domain and on ...
Methods and compositions using populations of randomized modified FRT recombination sites to identify, isolate and/or characterize modified FRT recombination sites are provided. The recombinogenic mod
RAD54, a significant homologous recombination proteins, is an associate from the SWI2/SNF2 category of ATPase-dependent DNA translocases. as well as the role from the RAD54 ATPase activity with this activation is definitely controversial. Its been demonstrated that RAD54 forms a co-complex with RAD51-ssDNA filaments, stabilizing the filament in a fashion that is definitely self-employed of ATP hydrolysis by RAD54 (22, 25). Nevertheless, RAD54 mutants faulty in ATP hydrolysis neglect to stimulate RAD51 DNA strand exchange, indicating that extra downstream mechanisms are essential for the activation (14, 16, 26). Its been recommended that, through the seek out homology, binding of dsDNA by RAD54 and its own ATPase-dependent translocation along the RAD51-ssDNA filament may activate DNA strand exchange by either offering rapid delivery from the inbound dsDNA for the homology sampling by RAD51 or by locally disrupting the dsDNA foundation pairs, producing them available for the homology search from ...
Plasmids are important members of the bacterial mobile gene pool, and are among the most important contributors to horizontal gene transfer between bacteria. They typically harbour a wide spectrum of host beneficial traits, such as antibiotic resistance, inserted into their backbones. Although these inserted elements have drawn considerable interest, evolutionary information about the plasmid backbones, which encode plasmid related traits, is sparse. Here we analyse 25 complete backbone genomes from the broad-host-range IncP-1 plasmid family. Phylogenetic analysis reveals seven clades, in which two plasmids that we isolated from a marine biofilm represent a novel clade. We also found that homologous recombination is a prominent feature of the plasmid backbone evolution. Analysis of genomic signatures indicates that the plasmids have adapted to different host bacterial species. Globally circulating IncP-1 plasmids hence contain mosaic structures of segments derived from several parental plasmids that
Coordination between DNA replication and DNA repair ensures maintenance of genome integrity, which is lost in cancer cells. Lesions and discontinuities in the DNA template undergoing replication induce replication fork stalling. Homologous recombination (HR) proteins RAD51 and BRCA1/2 play a major role in the stability of replication forks. This function appears to be distinct from the classical one performed by these proteins in HR dependent DNA Double Strand Break repair.
TY - JOUR. T1 - A study of electron recombination using highly ionizing particles in the ArgoNeuT Liquid Argon TPC. AU - Acciarri, R.. AU - Adams, C.. AU - Asaadi, J.. AU - Baller, B.. AU - Bolton, T.. AU - Bromberg, C.. AU - Cavanna, F.. AU - Church, E.. AU - Edmunds, D.. AU - Ereditato, A.. AU - Farooq, S.. AU - Fleming, B.. AU - Greenlee, H.. AU - Horton-Smith, G.. AU - James, C.. AU - Klein, E.. AU - Lang, K.. AU - Laurens, P.. AU - McKee, D.. AU - Mehdiyev, R.. AU - Page, B.. AU - Palamara, O.. AU - Partyka, K.. AU - Rameika, G.. AU - Rebel, B.. AU - Soderberg, M.. AU - Spitz, J.. AU - Szelc, A. M.. AU - Weber, M.. AU - Wojcik, M.. AU - Yang, T.. AU - Zeller, G. P.. PY - 2013/8/1. Y1 - 2013/8/1. N2 - Electron recombination in highly ionizing stopping protons and deuterons is studied in the ArgoNeuT detector. The data are well modeled by either a Birks model or a modified form of the Box model. The dependence of recombination on the track angle with respect to the electric field direction is ...
... and genetic recombination[edit]. Meiosis results in a random segregation of the genes that each parent ... In addition, it is thought by some,[40] that a long-term advantage of out-crossing in nature is increased genetic variability ... One is that it evolved from prokaryotic sex (bacterial recombination) as eukaryotes evolved from prokaryotes.[6] The other is ... Otto, S.P; Gerstein, A.C (2006). "Why have sex? The population genetics of sex and recombination". Biochemical Society ...
"Genetic Recombination , Learn Science at Scitable". Retrieved 2015-11-13. Yamada, Kazuhiro; Ariyoshi, Mariko; ... Branch migration is the second step of genetic recombination, following the exchange of two single strands of DNA between two ... present during recombination. The ions determine which structure the Holliday junction will adopt, as they play a stabilizing ... influencing the degree of which the genetic material is exchanged. Branch migration can also be seen in DNA repair and ...
"genetic recombination". Genetic Recombination Smith, George P. (1 January 1976). "Evolution of Repeated DNA Sequences by ... It is one of the final phases of genetic recombination, which occurs in the pachytene stage of prophase I of meiosis during a ... This leads to the notion of "genetic distance", which is a measure of recombination frequency averaged over a (suitably large) ... Surtees, J. A., J.A.; Argueso, J.L.; Alani, E. (2004). "Mismatch Repair Proteins: Key Regulators of Genetic Recombination". ...
Synthetic genetic array Saccharomyces cerevisiae Ascus Homologous recombination Genetic recombination Ascospore Perkins, D.D. ( ... Genetic Recombination. New York: Wiley; 1982. ISBN 978-0471102052 Yeast Protocols: Methods in Cell and Molecular Biology, Ivor ... These studies have proven central to understanding the mechanism of meiotic recombination, which in turn is a key to ... The use of tetrads in fine-structure genetic analysis is described in the articles Neurospora crassa and Gene conversion. ...
They are also used in DNA repair and genetic recombination.[120] Topoisomerases and helicases. Topoisomerases are enzymes with ... Non-homologous recombination can be damaging to cells, as it can produce chromosomal translocations and genetic abnormalities. ... Recombination allows chromosomes to exchange genetic information and produces new combinations of genes, which increases the ... The recombination reaction is catalyzed by enzymes known as recombinases, such as RAD51.[132] The first step in recombination ...
Analysis of genetic recombination is facilitated by the ordered arrangement of the products of meiosis in Neurospora ascospores ... 1982). Genetic Recombination. Wiley, New York ISBN 978-0471102052 Leslie JF, Raju NB (December 1985). "Recessive mutations from ... An understanding of recombination is relevant to several fundamental biologic problems, such the role of recombination and ... of the molecular mechanism of recombination is discussed in the Wikipedia articles Gene conversion and Genetic recombination. ...
... particularly the analysis of the molecular mechanism of genetic recombination. When a wild type (+) strain is mated with a ... The natural habitat of the three species of Sordaria that have been the principal subjects in genetic studies is dung of ... These species share a number of characteristics that are advantageous for genetic studies. They all have a short life cycle, ... asci). The retention of the products of an individual meiosis in an individual ascus has facilitated certain kinds of genetic ...
Lederberg J (1955). "Genetic recombination in bacteria". Science. 122 (3176): 920. doi:10.1126/science.122.3176.920. PMID ... Wollman EL, Jacob F, Hayes W (1956). "Conjugation and genetic recombination in Escherichia coli K-12". Cold Spring Harbor ... In analogy with fertilization and meiosis of higher organisms, he proposed that all of the genetic material was transferred but ... If mating terminated before the prophage was transferred, phage was not produced, and recombination proceeded in the zygote. ...
Induced meiotic recombination". Mutat. Res. 12 (3): 269-79. doi:10.1016/0027-5107(71)90015-7. PMID 5563942. Bleuyard JY, ... Schewe MJ, Suzuki DT, Erasmus U (July 1971). "The genetic effects of mitomycin C in Drosophila melanogaster. II. ... In the fruit fly Drosophila melanogaster, exposure to mitomycin C increases recombination during meiosis, a key stage of the ... In the plant Arabidopsis thaliana, mutant strains defective in genes necessary for recombination during meiosis and mitosis are ...
... s are genetic recombination enzymes. DNA recombinases are widely used in multicellular organisms to manipulate the ... Dmc1 function appears to be limited to meiotic recombination. Like Rad51, Dmc1 is homologous to bacterial RecA. Some DNA ... Cre recombinase Hin recombinase Tre recombinase FLP recombinase Recombinases have a central role in homologous recombination in ... to form a presynaptic filament that is an intermediate in homologous recombination. ...
This recombination of genes allows for the introduction of new allele pairings and genetic variation. Genetic variation among ... Genetic crossing-over, a type of recombination, occurs during the pachytene stage of prophase I. In addition, another type of ... This proved interchromosomal genetic recombination. Homologous chromosomes are chromosomes which contain the same genes in the ... They allow for the recombination and random segregation of genetic material from the mother and father into new cells. Meiosis ...
Whitehouse, HLK (1982). Genetic Recombination: understanding the mechanisms. Wiley. p. 321 & Table 38. ISBN 978-0471102052. ... Formosa T, Alberts BM (December 1986). "DNA synthesis dependent on genetic recombination: characterization of a reaction ... Similarly, S. cerevisiae Sgs1, an ortholog of BLM, appears to be a central regulator of most of the recombination events that ... Data based on tetrad analysis from several species of fungi show that only a minority (on average about 34%) of recombination ...
This process is known as genetic recombination. The rate of recombination of two discrete loci corresponds to their physical ... daughter cells have the greatest amount of genetic diversity. (Click Here for a video tutorial explaining genetic recombination ... "Genetic Recombination and Gene Mapping , Learn Science at Scitable". Retrieved 2016-04-10. Single, Richard M.; ... "Genetic Recombination and Gene Mapping , Learn Science at Scitable". Retrieved 2016-04-10. Palhares, Alessandra ...
Marrs B (March 1974). "Genetic recombination in Rhodopseudomonas capsulata". Proceedings of the National Academy of Sciences of ... If the sequences are not identical this will produce a cell with a new genetic combination. However, if the incoming DNA is not ... Most of the RcGTA structural genes are encoded in a ~ 15 kb genetic cluster on the bacterial chromosome. However, other genes ... One alternative explanation is that GTA genes persist because GTAs are genetic parasites that spread infectiously to new cells ...
Marrs B (March 1974). "Genetic recombination in Rhodopseudomonas capsulata". Proceedings of the National Academy of Sciences of ... Lang AS, Beatty JT (January 2000). "Genetic analysis of a bacterial genetic exchange element: the gene transfer agent of ... The genetic material had a high GC content at 66.6%. R. capsulatus contains all of the genes necessary to produce all 20 amino ... A small filterable agent was soon identified as the source of this genetic exchange. When a mutant strain that over-produced ...
Recombination and genetic linkageEdit. Main articles: Chromosomal crossover and Genetic linkage ... He described several rules of genetic inheritance in his work The genetic law of the Nature (Die genetische Gesätze der Natur, ... genetic, adj., Oxford English Dictionary, 3rd ed. *^ Richmond ML (November 2007). "Opportunities for women in early genetics". ... genetic drift, genetic hitchhiking,[87] artificial selection and migration.[88] ...
... and genetic recombinationEdit. Meiosis results in a random segregation of the genes that each parent contributes ... In addition, it is thought by some,[32] that a long-term advantage of out-crossing in nature is increased genetic variability ... Otto, SP; Gerstein, AC (2006). "Why have sex? The population genetics of sex and recombination". Biochem Soc Trans. 34 (4): 519 ... Abbott, RJ; Gomes, MF (1989). "Population genetic structure and outcrossing rate of Arabidopsis thaliana (L.) Heynh". Heredity ...
Recombination has been shown to occur between the minichromosomes. While slight variations on the standard genetic code had ... What recombination does take place maintains genetic integrity rather than maintaining diversity. However, there are studies ... The near-absence of genetic recombination in mitochondrial DNA makes it a useful source of information for studying population ... Three Billion Years of Genetic Recombination. New Haven: Yale University Press. pp. 69-71, 87. ISBN 978-0-300-03340-3. Martin ...
... genetic recombination usually occurs. Some of the recombination events occur by crossing over (involving physical exchange ... CO recombination may also be initiated by external sources of DNA damage such as X-irradiation, or internal sources. There is ... This is because, at the end of meiotic prophase I, CO recombination provides a physical link that holds homologous chromosome ... Sonntag Brown M, Lim E, Chen C, Nishant KT, Alani E (2013). "Genetic analysis of mlh3 mutations reveals interactions between ...
... where regions of low recombination in the genome exhibit low levels of genetic variation. Hudson and Kaplan showed that the ... The genetic basis for evolutionary change. Columbia Univ. Press, New York, NY. Hudson, Richard R. and Norman L. Kaplan. 1995. ... In areas of high recombination, neutral loci are more likely to 'escape' the effects of nearby selection and be retained in the ... The name emphasizes the fact that the genetic background, or genomic environment, of a neutral mutation has a significant ...
In collaboration with Jean Weigle, Meselson then applied the density gradient method to studies of genetic recombination in the ... Meselson, M.; Weigle, J. (1961). "Chromosome Breakage Accompanying Genetic Recombination in Bacteriophage". Proceedings of the ... genetic recombination, and aging. Many of his past students are notable biologists, including Nobel Laureate Sidney Altman, as ... "A General Model for Genetic Recombination". Proceedings of the National Academy of Sciences USA. 72 (1): 358-361. Bibcode: ...
Recombination. Further information: Genetic recombination. Two RNA genomes are encapsidated in each HIV-1 particle (see ... Viral recombination produces genetic variation that likely contributes to the evolution of resistance to anti-retroviral ... This form of recombination is known as copy-choice. Recombination events may occur throughout the genome. Anywhere from two to ... "High frequency of genetic recombination is a common feature of primate lentivirus replication". Journal of Virology. 80 (19): ...
Recombination[edit]. When two viruses infect the same cell, genetic recombination may occur.[46] Although infrequent, HCV ... Based on genetic differences between HCV isolates, the hepatitis C virus species is classified into six genotypes (1-6) with ... 2009). "Genetic variation in IL28B predicts hepatitis C treatment-induced viral clearance". Nature. 461 (7262): 399-401. ... Kato N, Ueda Y, Sejima H, Gu W, Satoh S, Dansako H, Ikeda M, Shimotohno K (2019) Study of multiple genetic variations caused by ...
In S phase, the chromosomes are replicated in order for the genetic content to be maintained. During G2, the cell undergoes the ... Keeney S (2001). Mechanism and control of meiotic recombination initiation. Current Topics in Developmental Biology. 52. ... Griffiths AJ (2012). Introduction to genetic analysis (10th ed.). New York: W.H. Freeman and Co. ISBN 9781429229432. OCLC ... Prokaryotes (bacteria and archaea) usually undergo a vegetative cell division known as binary fission, where their genetic ...
Genetic recombination can occur when at least two viral genomes are present in the same infected host cell. RNA recombination ... Recombination can determine genetic variability within a CoV species, the capability of a CoV species to jump from one host to ... Epidemiology, Genetic Recombination, and Pathogenesis of Coronaviruses. Trends Microbiol. 2016 Jun;24(6):490-502. doi: 10.1016/ ... The exact mechanism of recombination in CoVs is not known, but likely involves template switching during genome replication. ...
As many coronaviruses exist in nature, their genetic recombination can result in the formation of novel viruses, making targets ... Genetic Recombination, and Pathogenesis of Coronaviruses". Trends in Microbiology. 24 (6): 490-502. doi:10.1016/j.tim.2016.03. ...
In addition to mutation, RNA virus evolution is also facilitated by genetic recombination. Genetic recombination can occur when ... a form of genetic recombination. Recombination also occurs in the Coronaviridae ((+)ssRNA) (e.g. SARS). Recombination in RNA ... June 2016). "Epidemiology, Genetic Recombination, and Pathogenesis of Coronaviruses". Trends in Microbiology. 24 (6): 490-502. ... RNA is also believed to have been the genetic material of the first life on Earth. The role of RNA in the origin of life is ...
Numerous RNA viruses are capable of genetic recombination when at least two viral genomes are present in the same host cell. ... June 2016). "Epidemiology, Genetic Recombination, and Pathogenesis of Coronaviruses". Trends in Microbiology. 24 (6): 490-502. ... a form of recombination. Recombination also occurs in the Reoviridae (dsRNA)(e.g. reovirus), Orthomyxoviridae ((-)ssRNA)(e.g. ... The genetic diversity of RNA viruses is one reason why it is difficult to make effective vaccines against them. Retroviruses ...
... (1919-2011) was a Swiss molecular biologist known for her discoveries on genetic recombination and ... Meselson, M.; Weigle, J. J. (1961-06-15). "Chromosome brekage accompanying genetic recombination in bacteriophage". Proceedings ... She was a pioneer in the genetic analysis of bacteriophages and contributed to the early development of molecular biology. ... From 1971-1975, she worked with Douglas Berg, with whom she shared an interest in genetic analysis of bacteriophages and ...
While schizophrenia is widely believed to be multifactorially genetic by biopsychiatrists, no characteristic genetic markers ... and the apparent QTL effect at a marker will be smaller than the true QTL effect as a result of recombination between the ... then there is a strong chance that the disease is genetic[citation needed] and that the patient will also be a genetic carrier ... If a genetic cause is suspected and little else is known about the illness, then it remains to be seen exactly how many genes ...
"Mobile Genetic Elements. 3 (4): e25845. doi:10.4161/mge.25845. PMC 3812789. PMID 24195014.. ... One of the main competing models for cpDNA asserts that most cpDNA is linear and participates in homologous recombination and ... It further contends that only a minority of the genetic material is kept in circular chromosomes while the rest is in branched ... homologous recombination does not explain the multiple A → G gradients seen in plastomes.[17] This shortcoming is one of the ...
In recognition of his discovery of somatic recombination in fungi which led to the elucidation of an important type of genetic ... developing models for the evolution of genetic systems, including sex and recombination, inbreeding and outbreeding, separate ... They have combined molecular and genetic approaches to answer some of Darwins key questions about the natural variation of ... For his work on extended oceanographical expeditions; and for his genetic studies in animals and plants. ...
Resistance to recombination[edit]. A1::DQ2 is found in Iceland, Pomors of Northern Russia, the Serbians of Northern Slavic ... This compares with 25% of Cw7-B7 that extend to A3::DQ6 [4] Of 25 potential genetic recombinants of A1::DQ2, none exceed 10% of ... Recombination dynamics[edit]. Each person has unique chromosomes, unless they are identical twins. These unique chromosomes are ... Genetics of recombination in humans suggests that common haplotypes of this length that Cw7-B8 component should be in other ...
"Genetic Evaluation Results". Archived from the original on August 27, 2001.. *^ S1008: Genetic Selection and Crossbreeding to ... Despite all its disadvantages, inbreeding can also have a variety of advantages, such as reducing the recombination load,[21] ... "Genetic diversity and population genetic structure in the South American sea lion (Otaria flavescens)" (PDF). Department of ... There are genetic assays being scheduled for lions to determine their genetic diversity. The preliminary studies show results ...
... scientists instead focused on how uncoupled phenotypic traits can be affected by genetic recombination and mutations, applying ... Pleiotropy describes the genetic effect of a single gene on multiple phenotypic traits. The underlying mechanism is genes that ... Sickle cell anemia is a genetic disease that causes deformed red blood cells with a rigid, crescent shape instead of the normal ... This article is about genetic pleiotropy. For drug pleiotropy, see Pleiotropy (drugs). ...
10.0 10.1 10.2 Market E & Papavasiliou FN (2003). "V(D)J recombination and the evolution of the adaptive immune system". PLoS ... Several complex genetic mechanisms have evolved. These allow vertebrate B cells to generate a huge pool of antibodies from a ...
mitotic recombination-dependent replication fork processing. • reciprocal meiotic recombination. • DNA recombination. • ... "Genetic unmasking of an epigenetically silenced microRNA in human cancer cells". Cancer Res. 67 (4): 1424-9. doi:10.1158/0008- ... mitotic recombination. • protein homooligomerization. • response to toxic substance. • DNA repair. • response to X-ray. • ... Further steps are detailed in the article Homologous recombination.. Meiosis[edit]. Rad51 has a crucial function in meiotic ...
Recombination rates exceeded those of uninduced cultures by up to three orders of magnitude. Frols et al.[150][152] and Ajon et ... Gene transfer and genetic exchangeEdit. Halobacterium volcanii, an extreme halophilic archaeon, forms cytoplasmic bridges ... Current knowledge on genetic diversity is fragmentary and the total number of archaeal species cannot be estimated with any ... Aside from the similarities in cell structure and function that are discussed below, many genetic trees group the two. ...
They can be wide (gradual) or narrow (steep) depending on the ratio of hybrid survival to recombination of genes.[5] Hybrid ... These are alleles that are normally rare in both species but, probably due to genetic hitchhiking on genes for hybrid fitness, ... Based on the fossil record and genetic marker studies the following chronology is used to explain the Canadian mussel hybrid ... Hybrid zones are areas where the hybrid offspring of two divergent taxa (species, subspecies or genetic "forms") are prevalent ...
Lu Y, Dollé ME, Imholz S, van 't Slot R, Verschuren WM, Wijmenga C, Feskens EJ, Boer JM (Dec 2008). "Multiple genetic variants ... Hartley JL, Temple GF, Brasch MA (Nov 2000). "DNA cloning using in vitro site-specific recombination". Genome Research. 10 (11 ...
遺傳重組會交換不同染色體或同一染色體的不同區域之間的基因,而打破遺傳連鎖,讓基因能夠自由組合,並降低遺傳便車效應(genetic hitchhiking)。這使得天擇更有效率,因此,重組率高的區域會保留較少有
... genetic polymorphism ... V(D)J recombination. *Junctional diversity. *Immunoglobulin ...
Hall JD, Scherer K (1981). "Repair of psoralen-treated DNA by genetic recombination in human cells infected with herpes simplex ... effects of mutations influencing genetic recombination and DNA metabolism". J. Bacteriol. 136 (2): 538-47. doi:10.1128/JB.136.2 ... mechanism and genetic control". J. Mol. Biol. 103 (1): 39-59. doi:10.1016/0022-2836(76)90051-6. PMID 785009.. ... the recombination events associated with crosslink removal by HRR are predominantly non-crossover gene conversion events. ...
Thomson, James A.; Zwaka (2003년 2월 10일). "Homologous recombination in human embryonic stem cells". 》Nature Biotechnology》 21 (3 ... "Human embryonic stem cell lines with genetic disorders". 》Reproductive Biomedicine Online》 10 (1): 105-110. ISSN 1472-6483 ... "DNA repair by nonhomologous end joining and homologous recombination during cell cycle in human cells". 》Cell Cycle ( ... "Mouse embryonic stem cells, but not somatic cells, predominantly use homologous recombination to repair double-strand DNA ...
Genetic mosaics can also be created through mitotic recombination. Such mosaics were originally created by irradiating flies ... Mitotic recombination[edit]. One basic mechanism which can produce mosaic tissue is mitotic recombination or somatic crossover ... "Genetic mosaics in animals and man". pp27-129, in Stern, C. Genetic Mosaics and Other Essays. Harvard University Press, ... Curt Stern demonstrated that genetic recombination, normal in meiosis, can also take place in mitosis.[21][22] When it does, it ...
Grete Kellenberger-Gujer (1919-2011): Swiss molecular biologist known for her discoveries on genetic recombination and ... She was a pioneer in the genetic analysis of bacteriophages and contributed to the early development of molecular biology.[181] ... Brenner made significant contributions to work on the genetic code, and other areas of molecular biology while working in the ... Hermann Joseph Muller (1890-1967): American geneticist and educator, best known for his work on the physiological and genetic ...
Woese C.R. (1967). The genetic code: The molecular basis for genetic expression. p. 186. Harper & Row ... "A novel virus genome discovered in an extreme environment suggests recombination between unrelated groups of RNA and DNA ... Cairns-Smith AG (1993). Genetic Takeover: And the Mineral Origins of Life. Cambridge University Press. ISBN 978-0-521-23312-5. ... Crick FH (Dec 1968). "The origin of the genetic code". Journal of Molecular Biology. 38 (3): 367-79. doi:10.1016/0022-2836(68) ...
... during a genetic recombination event. It is thought to be a very ancient gene, about 3500 years old, and is widely distributed ... Genetic testing is available to help determine the presence of the Tobiano gene. Originally, there was no direct test for ... This inversion was finally mapped for genetic testing and is now offered by several laboratories.[1] Testing is most often ... Tobiano, the early Tobiano tests utilized six genetic markers, including a marker on the KIT gene on horse chromosome 3, which ...
Quantitative genetics focuses on genetic variance due to genetic interactions. Any two locus interactions at a particular gene ... "Coevolution of robustness, epistasis, and recombination favors asexual reproduction". Proceedings of the National Academy of ... In this regression, the observed two locus genetic effects are treated as dependent variables and the "pure" genetic effects ... Genetic and molecular causes[edit]. Additivity[edit]. This can be the case when multiple genes act in parallel to achieve the ...
Baillie BK, Belda-Baillie C A,, Silvestre V, Sison M, Gomez AV, Gomez ED, Monje V (2000). Genetic variation in Symbiodinium ... Host-symbiont recombination vs. natural selection in the response of coral-dinoflagellate symbioses to environmental ... 32,0 32,1 Sampayo E, Dove S, LaJeunesse TC (2009) Cohesive molecular genetic data delineate species diversity in the ... Andras J P, Kirk NL, Harvell CW (2011) Range-wide population genetic structure of Symbiodinium associated with the Caribbean ...
Large study provides new insights in autism's genetic code (sa wikang Ingles) ... RAG1/RAG2: recombination activating genes. Mga sakit at diperensiya[baguhin , baguhin ang batayan]. ...
Furthermore, semiconductor lasers can be modulated directly at high frequencies because of short recombination time. ... Genetic engineering *Gene therapy. *Head transplant. *Isolated brain. *Life extension *Strategies for Engineered Negligible ...
Genetic origins. Main article: Genetic studies on Jews. Efforts to identify the origins of Ashkenazi Jews through DNA analysis ... Both segments are unaffected by recombination (except for the ends of the Y chromosome - the pseudoautosomal regions known as ... The genome-wide genetic study carried out in 2010 by Behar et al. examined the genetic relationships among all major Jewish ... Genetic counseling and genetic testing are often undertaken by couples where both partners are of Ashkenazi ancestry. Some ...
Retroviral integrase (IN) is an enzyme produced by a retrovirus (such as HIV) that enables its genetic material to be ... Retroviral INs are not to be confused with phage integrases, such as λ phage integrase (Int) (see site-specific recombination ... see site specific recombination). HIV integrase is a 32 kDa protein produced from the C-terminal portion of the Pol gene ...
It arises mainly from genetic recombination of the DNA encoded segments in individual somatic T cells by somatic V(D)J ... The TCR alpha chain is generated by VJ recombination, whereas the beta chain is generated by VDJ recombination (both involving ... Likewise, generation of the TCR gamma chain involves VJ recombination, whereas generation of the TCR delta chain occurs by VDJ ... The recombination process that creates diversity in BCR (antibodies) and TCR is unique to lymphocytes (T and B cells) during ...
The male bees' genetic makeup is therefore entirely derived from the mother, while the genetic makeup of the female worker bees ... "Unusually high recombination rate detected in the sex locus region of the honey bee (Apis mellifera)". Genetics. 153 (4): 1701 ... Several models have been proposed for the genetic mechanisms of haplodiploid sex-determination. The model most commonly ...
Lamb MJ, Jablonka E (2005). Evolution in four dimensions: genetic, epigenetic, behavioral, and symbolic variation in the ... good enough for short-term adaptation that allows the lineage to survive for long enough for mutation and/or recombination to ... These are normal genetic diseases caused by gene deletions or inactivation of the genes, but are unusually common because ... It could confer an adaptive advantage by giving cells the ability to switch into a PSI+ state and express dormant genetic ...
Genetic driftEdit. Even if a well adapted Y chromosome manages to maintain genetic activity by avoiding mutation accumulation, ... Recombination inhibitionEdit. Recombination between the X and Y chromosomes proved harmful-it resulted in males without ... National Library of Medicine's Genetic Home Reference *^ "Definition of holandric ,". ... In human genetic genealogy (the application of genetics to traditional genealogy), use of the information contained in the Y ...
Margulis, Lynn; Sagan, Dorion (1986). Origins of sex: three billion years of genetic recombination. The Bio-origins series. New ...
Although a number of steps in recombination have been well characterized, many other details about this process remain ... DNA recombination occurs frequently in many different cell types, and it has important implications for genomic integrity, ... Although common, genetic recombination is a highly complex process. It involves the alignment of two homologous DNA strands ( ... DNA recombination involves the exchange of genetic material either between multiple chromosomes or between different regions of ...
... All organisms suffer a certain number of small mutations, or random changes in a DNA sequence, during ... Genetic recombination refers more to a large-scale rearrangement of a DNA molecule. This process involves pairing between ... The frequency of recombination is actually not the same for all gene combinations. This is because recombination is greatly ... Recombination results in a new arrangement of maternal and paternal alleles on the same chromosome. Although the same genes ...
Animations showing several models of homologous recombination The Holliday Model of Genetic Recombination Genetic+recombination ... Genetic recombination (also known as genetic reshuffling) is the exchange of genetic material between different organisms which ... ordinarily precedes genetic recombination. Genetic recombination is catalyzed by many different enzymes. Recombinases are key ... the process during which homologous sequences are made identical also falls under genetic recombination. Genetic recombination ...
Genetic recombination (also known as genetic reshuffling) is the exchange of genetic material between different organisms which ... Genetic engineeringEdit. In genetic engineering, recombination can also refer to artificial and deliberate recombination of ... The Holliday Model of Genetic Recombination. *Genetic+recombination at the US National Library of Medicine Medical Subject ... RNA virus recombinationEdit. Numerous RNA viruses are capable of genetic recombination when at least two viral genomes are ...
... independently of recombinations at yl, l ≠ i. Let k be the number of recombinations generated. These k recombinations split the ... Recombinations: For i = 1, …, s − 1, generate a recombination at point yi with probability ziρ/(ziρ+ j), ... Estimating Recombination Rates From Population Genetic Data Message Subject (Your Name) has forwarded a page to you from ... A recombination between two neighboring loci. If the positions of the loci are xl and xl+1, and the recombination produces ...
Scientists in Rochester have discovered a gene in fruit flies that is responsible for the evolution of these recombination ... Genetic recombination is vital to natural selection, yet some species display far more crossover than others. ... The importance of genetic recombination. "Natural selection works best when theres a diversity of genotypes to act upon," says ... Genetic recombination is vital to natural selection, yet some species display far more crossover than others. Scientists in ...
... or chromosomal crossover is when chromosomes or regions of the same chromosome ... The main function of genetic recombination is to incorporate both genes of the male and female gamete, to boost genetic ... Prokaryotic Genetic Recombination and Types of Operons. Discuss the two different types of operons found in bacterial genomes ( ... Diversity from genetic recombination can increase the adaptability of organisms to survive in changing environment by ...
Types of recombination. Genetic recombination is initiated by nicks or breaks between base pairs in the donor dsDNA. There are ... Homologous Recombination from a Genetic Perspective. Recombination involves the cutting and covalent joining of DNA sequences. ... The genetic perspective of recombination is important because it has many practical implications, such as genetic mapping. ... a genetic selection is typically required to find a specific recombination event in vivo.) *The co-inheritance of two genetic ...
... wide human genetic data, understanding the role of recombination in determining patterns of genetic diversity is more important ... With the advent of genome‐wide human genetic data, understanding the role of recombination in determining patterns of genetic ... The relationship between the local recombination rate and patterns of genetic diversity. Shown at the top of the figure is the ... Recombination and Human Genetic Diversity. Chris CA Spencer, University of Oxford, Oxford, UK ...
The recombination frequency between gene "Q" and gene "Z" is found to be 23.5%. The recombination frequency between "Q" and a ... D is true because the recombination frequency between R and Z (13.5%) , the recombination frequency between R and Q (10%). ... third gene "R" is 10%. The frequency of recombination between "Z" and "R" is 13.5%. Which one of the following is NOT true ...
DNA »DNA sequences »chromosomes »fruit flies »genes »genetic elements »genetic material »melanogaster »natural selection ... Further reports about: , DNA , DNA sequences , chromosomes , fruit flies , genes , genetic elements , genetic material , ... Scientists have long recognized that the exchange of genetic material by crossing over--known as recombination--is vital to ... Rochester scientists discover gene controlling genetic recombination rates. 23.04.2018. Genetics is a crapshoot. During sexual ...
Genetic recombination before commitment to meiosis in Saccharomyces. Proc. Nat. Acad. Sci. U.S.A. in press.Google Scholar ... Esposito R.E., Plotkin D.J., Esposito M.S. (1974) The Relationship between Genetic Recombination and Commitment to Chromosomal ... The Relationship between Genetic Recombination and Commitment to Chromosomal Segregation at Meiosis. ... Genic Recombination Sporulation Medium Intragenic Recombination Meiotic Segregation Meiotic Product These keywords were added ...
DNA replication meets genetic exchange: Chromosomal damage and its repair by homologous recombination. Andrei Kuzminov ... DNA replication meets genetic exchange: Chromosomal damage and its repair by homologous recombination ... DNA replication meets genetic exchange: Chromosomal damage and its repair by homologous recombination ... DNA replication meets genetic exchange: Chromosomal damage and its repair by homologous recombination ...
Genetic recombination and complementation between bacteriophage T7 and cloned fragments of T7 DNA. J L Campbell, C C Richardson ... Genetic recombination and complementation between bacteriophage T7 and cloned fragments of T7 DNA ... Genetic recombination and complementation between bacteriophage T7 and cloned fragments of T7 DNA ... Genetic recombination and complementation between bacteriophage T7 and cloned fragments of T7 DNA ...
The problem with this idea is the fact that genetic recombination is now being shown to be a highly regulated and controlled ... Genetic recombination is directed away from functional genomic elements in mice. Nature. 485 (7400): 642-645. ... This process of exchanging DNA segments across sister chromatids is called genetic or homologous recombination and does not ... Evolutionists have speculated for years that genetic recombination is one of the key mechanisms generating mutations and ...
Mismatch repair stabilizes the cellular genome by correcting DNA replication errors and by blocking recombination events ... Mismatch repair in replication fidelity, genetic recombination, and cancer biology Annu Rev Biochem. 1996;65:101-33. doi: ... Mismatch repair stabilizes the cellular genome by correcting DNA replication errors and by blocking recombination events ...
Genetic Recombination and Linkage. Bacteria and Viruses. Clinicians Perspective: Pathology Meets Engineering. Classical ... You know while various recombination events are happening in various genetic eventsthat are happening some part of chromosomes ... And some recombination events might happen which is being transmitted fromone to next generation which happens usually during ... How many F2 plantsof each of the 4 phenotype do you expect?So, in the conclusion in today class we studied recombination of ...
View source for Genetic recombination/Related Articles. ← Genetic recombination/Related Articles. Jump to: navigation, search ...
... the effect of genetic recombination on a species capacity of adaptation. ... There has been much discussion of the evolutionary role of genetic recombination: the exchange of parental genetic material ... But what exactly is the advantage of recombination? This work shows that genetic recombination facilitates adaptation and it ... Evolutionary advantage of genetic recombination in the genome measured for first time. Universitat Autonoma de Barcelona ...
... Trends Microbiol. 2016 Jun;24(6):490-502. doi: 10.1016/j ... in addition to the virus evolution and recombination events which have, on occasion, resulted in outbreaks amongst humans. ...
During sexual reproduction, genes from both the mother and the father mix and mingle to produce a genetic combination unique to ... Scientists generate the most precise map of genetic recombination ever. July 10, 2008 Genetic recombination, the process by ... The importance of genetic recombination. "Natural selection works best when theres a diversity of genotypes to act upon," says ... Scientists discover gene controlling genetic recombination rates. April 20, 2018, University of Rochester ...
481: Genetic Toxicology: Saacharomyces cerevisiae, Miotic Recombination Assay Following the OECD Council decision, the Test ... Guideline 481 Genetic Toxicology: Saacharomyces cerevisiae, Miotic Recombination Assay was deleted on 2nd April 2014. ...
Meiosis and sexual reproduction, however, result in a reassortment of the genetic material. Thi ... This reassortment, called genetic recombination, originates from three events during the reproductive cycle: ... In many cases, however, this event may be affected by the genetic composition of a gamete. For example, some sperm may be ... Crossing over. During prophase I, nonsister chromatids of homologous chromosomes exchange pieces of genetic material. As a ...
Recombination affects the fate of alleles in populations by imposing constraints on the reshuffling of genetic information. ... Understanding the genetic basis of these constraints is critical for manipulating the recombination process to improve the ... a) Distribution of recombination rate (cM/Mb), genetic diversity, and deleterious allele density across the chromosomes group 7 ... The genetic architecture of genome-wide recombination rate variation in allopolyploid wheat revealed by nested association ...
... the process by which sexually reproducing organisms shuffle their genetic material when producing germ cells, leads to ... offspring with a new genetic make-up and influences the course of evolution. ... Scientists generate the most precise map of genetic recombination ever. July 10, 2008, Genetic recombination, the process by ... Scientists generate the most precise map of genetic recombination ever. July 10, 2008 Genetic recombination, the process by ...
Mick Bailey Genetic recombination between pathogens derived from humans and livestock has the potential to create novel ... Genetic Recombination between Human and Animal Parasites Creates Novel Strains of Human Pathogen. *. ... Here we investigated whether genetic recombination between subspecies of the protozoan parasite, Trypanosoma brucei, from ... Mick Bailey Genetic recombination between pathogens derived from humans and livestock has the potential to create novel ...
Phageλ encodes its own recombination system, the Red system, comprising Exo, β and γ proteins. In addition,λ encodes another ... This thesis focuses on determining the function of Orf in phage and bacterial recombination pathways by analysing its impact on ... Significantly, this would direct recombination down the bacterial RecA pathway of break restoration rather than the phage Red ... Experiments revealed that Orf interacts with bacterial and phage recombination proteins in the initial exchange step of ...
A Genetic Map and Recombination Parameters of the Human Malaria Parasite Plasmodium falciparum ... A Genetic Map and Recombination Parameters of the Human Malaria Parasite Plasmodium falciparum ... A Genetic Map and Recombination Parameters of the Human Malaria Parasite Plasmodium falciparum ... A Genetic Map and Recombination Parameters of the Human Malaria Parasite Plasmodium falciparum ...
We identified by linkage disequilibrium and recombination analyses only limited genetic recombination, which occurred ... Intensive transmission of virulent subtype IbA10G2 in the study area might have resulted in genetic recombination with other ... We conducted sequence analyses of 32 genetic loci of 53 C. hominis specimens isolated from a longitudinally followed cohort of ... A recombination test showed only limited genetic recombination at the gp60 locus. Thus, the high level of LD and limited ...
  • Note that a third model of recombination, synthesis-dependent strand annealing [SDSA], has also been proposed to account for the lack of crossover typical of recombination in mitotic cells and observed in some meiotic cells to a lesser degree. (
  • In both meiotic and mitotic cells, recombination between homologous chromosomes is a common mechanism used in DNA repair. (
  • The RAD51 protein is required for mitotic and meiotic recombination, whereas the DNA repair protein, DMC1, is specific to meiotic recombination. (
  • A current model of meiotic recombination, initiated by a double-strand break or gap, followed by pairing with an homologous chromosome and strand invasion to initiate the recombinational repair process. (
  • Jeffreys AJ, Kauppi L and Neumann R (2001) Intensely punctate meiotic recombination in the class II region of the major histocompatibility complex. (
  • 2004) Meiotic recombination hot spots and human DNA diversity. (
  • MMR proteins also act during genetic recombination in steps that include repairing mismatches in heteroduplex DNA, modulating meiotic crossover control, removing 3' non-homologous tails during double-strand break repair, and preventing recombination between divergent sequences. (
  • I will present our work using genome-wide methods to map meiotic recombination, primarily in the model plant Arabidopsis thaliana. (
  • From our maps of recombination it is clear that centromeric regions are suppressed for meiotic crossovers. (
  • We are combining these technologies with classical genetics in order to ask, (i) which recombination pathways mediate changes to centromere satellite arrays, (ii) to what extent is mitotic versus meiotic recombination involved, and (iii) what are the roles of epigenetic marks? (
  • 10,000 bovine sperm cells to perform an extensive characterization of meiotic recombination in male cattle. (
  • hereditary markers were released at described physical ranges from we discovered the meiotic recombination rate of recurrence to become ~20% between and a flanking marker at 5, 10, 50, or 100 kilobases from the proper border. (
  • Nevertheless, a well-known meiotic feature can be that recombination isn't randomly distributed over the genome: coldspots and hotspots can be found, implying some regions frequently go through exchange more. (
  • Meiotic recombination occasions are not arbitrary and occur more often in certain parts of the genome (recombination hotspots), where double-stranded DNA breaks (DSBs) tend to be preferentially induced. (
  • That is a common phenomenon in lots of eukaryotes where meiotic recombination continues to be researched [1]. (
  • In meiotic recombination hotspots and coldspots have already been mapped utilizing a microarray-based strategy internationally, and although there is absolutely no single characteristic distributed by all hotspots, a higher G + C foundation structure is correlated with an elevated occurrence of DSBs [3] significantly. (
  • Crossover generated by meiotic recombination is a fundamental event that facilitates meiosis and sexual reproduction. (
  • In eukaryotes, meiotic recombination promotes genetic variation by reciprocal exchange of genetic materials between maternal and paternal homologs and introduction of new combinations of genetic variants into future generations. (
  • As a fundamental biological process, the genetic mechanisms of meiotic recombination are conserved across all eukaryotic species [ 3 ]. (
  • I would like to review studies on homologous and non-homologous recombination, meiotic and somatic recombination, and the applications of basic mechanisms of recombination today, such as genetically modified plants and foods. (
  • The process is similar to that in meiotic recombination, and has its possible advantages, but it's usually harmful and can result in tumors. (
  • Hypothesis testing of meiotic recombination rates from population genetic data. (
  • Meiotic recombination, one of the central biological processes studied in population genetics, comes in two known forms: crossovers and gene conversions. (
  • Our methodology provides a necessary complement to the existing procedures of estimating meiotic recombination rates from population genetic data. (
  • Homologous recombination occurs in eukaryotes , typically during the first phase of the meiotic cell division cycle. (
  • One important instance of recombination in diploid eukaryotic organisms is the exchange of genetic information between newly duplicated chromosomes during the process of meiosis . (
  • In eukaryotes, genetic recombination during meiosis can lead to a novel set of genetic information that can be passed on from the parents to the offspring. (
  • During meiosis in eukaryotes, genetic recombination involves the pairing of homologous chromosomes. (
  • In meiosis and mitosis, recombination occurs between similar molecules of DNA (homologous sequences). (
  • In meiosis, non-sister homologous chromosomes pair with each other so that recombination characteristically occurs between non-sister homologues. (
  • During meiosis, synapsis (the pairing of homologous chromosomes) ordinarily precedes genetic recombination. (
  • In eukaryotes, recombination during meiosis is facilitated by chromosomal crossover. (
  • Chromosomal crossover involves recombination between the paired chromosomes inherited from each of one's parents, generally occurring during meiosis. (
  • In this review we will, first, discuss roles for MMR proteins in repairing mismatches that occur during recombination, particularly during meiosis. (
  • 1974. Genetic recombination before commitment to meiosis in Saccharomyces. (
  • Esposito R.E., Plotkin D.J., Esposito M.S. (1974) The Relationship between Genetic Recombination and Commitment to Chromosomal Segregation at Meiosis. (
  • When sperm and egg cells are formed in humans and various animals, the process of meiosis generates genetic variation. (
  • In sexual organisms recombination occurs during the process of meiosis, which produces the sexual cells, and maintenance of this sophisticated mechanism, which systematises recombination to the whole genome, is the usual reason given for the preponderance of sex. (
  • Meiosis and sexual reproduction, however, result in a reassortment of the genetic material. (
  • In order to generate germ cells, sexually reproducing organisms undergo a complex series of cell divisions (meiosis) that includes the shuffling of genetic material inherited from the two parents. (
  • On average over 150 recombination events were observed during a typical meiosis. (
  • Different mechanisms of recombination, such as meiosis or mitotic rearrangement of chromosomes, have been proposed for wine strains. (
  • This putative mechanism involves mitotic recombination between homologous sequences and does not necessarily imply meiosis. (
  • During meiosis, homologous chromosomes undergo recombination, which can result in reciprocal crossover and gene conversion. (
  • Meiosis and recombination have a profound effect on natural genetic variation and genome evolution, which in turn has strategic importance for crop breeding. (
  • Reciprocal recombination between homologues fulfills an essential mechanistic role during meiosis in most organisms [1] , [2] . (
  • Genetic recombination occurs at meiosis, following cross-fertilization of gametes of parasites with different genotypes. (
  • In addition to recombination at meiosis, it is also clear that genetic changes can occur during asexual multiplication of P. falciparum blood forms, as shown by deletions of regions of certain chromosomes during in vitro culture. (
  • Intro Enhanced hereditary recombination is a hallmark of acts and meiosis two fundamental features. (
  • Therefore, a series of events unfold during meiosis, including pairing, synapses, and recombination between homologous chromosomes, to ultimately ensure the successful completion of this task. (
  • There are several phases involved in each recombination event during Meiosis I and Meiosis II. (
  • In eukaryotes recombination commonly occurs during meiosis as chromosomal crossover between paired chromosomes. (
  • Chromosomal crossover refers to recombination between the paired chromosomes inherited from each of one's parents, generally occurring during meiosis . (
  • In meiosis, several interesting events may happen along the way to provide genetic recombination , an unexpected change in the hereditary genetic material. (
  • Spontaneous mistakes occur during meiosis that lead to gametes with unusual changes in their genetic structure (makeup). (
  • There are opportunities described next to increase genetic variability during meiosis. (
  • In meiosis and mitosis, recombination occurs between homologous that is similar molecules (homologs) of DNA. (
  • Note that recombination is also observed in mitosis , but it doesn't occur as often in mitosis as it does in meiosis. (
  • Our cells carry out general recombination during meiosis. (
  • Identify two ways that meiosis contributes to genetic recombination. (
  • Students will understand how the genetic linkage of loci on chromosomes, such as genes and microsatellite molecular markers, affects the assortment of alleles during meiosis and phenotypes observed in a population. (
  • Predict how recombination frequency between two linked loci affects the genotype frequencies of the products of meiosis compared to loci that are unlinked (or very tightly linked). (
  • In this instance, the outcome of recombination is to ensure that each gamete includes both maternally and paternally derived genetic information, such that the resulting offspring will inherit genes from all four of its grandparents, thereby acquiring a maximum amount of genetic diversity. (
  • If two genes are located close together on a chromosome, the likelihood that a recombination event will separate these two genes is less than if they were farther apart. (
  • Linkage disequilibrium describes a situation in which some combinations of genes or genetic markers occur more or less frequently in a population than would be expected from their distances apart. (
  • The shuffling of genes brought about by genetic recombination produces increased genetic variation. (
  • During sexual reproduction, genes from both the mother and the father mix and mingle to produce a genetic combination unique to each offspring. (
  • Recombination can shuffle these combinations of genes so that some will be bad and those offspring will die, but some will be good and these offspring will survive. (
  • Evolutionists have speculated for years that genetic recombination is one of the key mechanisms generating mutations and resulting in new genes and regulatory DNA sequences. (
  • So, just you know refresh you in recombination is an event whenthese genes are getting recombined and they are getting an exchange from these two chromosomesand at a site. (
  • So, thisis how the cross should ideally look like.And so now if you take this situation that you have wild type with two features.And what you are looking at studying two genes and are they linked to each other or are theygoing to you know separate in the process of recombination. (
  • The study sheds light on fundamental questions about genetic shuffling and has implications for the tracking of disease genes and their inheritance. (
  • Both types of recombination can also act to separate the transmission of neighbouring genes, which are normally inherited together. (
  • Homologous recombination is a fundamental cellular process that rearranges genes both within and between chromosomes, promotes repair of damaged DNA and underpins replication. (
  • One strategy to identify such components is to positionally clone the genes and variants that underlie inherited variation in recombination phenotypes. (
  • The aim of the study was to determine genetic linkage between gene pairs, Co-4 2 / Phg-2 , on bean-chromosome Pv08 and Co-5 /"P.ult" on-chromosome Pv07, to increase the efficiency of dual selection of resistance genes for major bean diseases, with molecular markers. (
  • Generally, the weak or incomplete genetic linkage between marker pairs studied showed that all the four genes mentioned earlier have to be tagged with a corresponding linked marker during selection. (
  • Mapping intraspecies recombination sites within the polyprotein highlighted recombinant hotspots in nonstructural genes and at gene boundaries. (
  • Taken together, our results suggest that only intraspecies recombination gives rise to viable rhinovirus chimeras in the polyprotein coding region and that recombination hotspots map to nonstructural genes with in-frame duplications at gene boundaries. (
  • 98 (54.7%) of these genes were involved in homologous recombination, indicating that foreign genetic fragments may have caused the adaptive diversification, especially in lineages with nutritional transitions. (
  • A Bayesian temporal reconstruction of CVA6 evolution since 2004 provided estimates of dates and the actual recombination events that generated more recently appearing recombination groups (RF-E, -F, -G and -H). Associations were observed between recombination groups and clinical presentations of herpangina, aHFMD and eczema herpeticum, but not with VP1 or other structural genes. (
  • Several genes, including RNF212 , CPLX1 and PRDM9 , were associated with individual-level recombination rate across multiple species. (
  • Genetics is a branch of biology concerned with the study of genes , genetic variation , and heredity in living organisms . (
  • Genetic recombination is defined as the rearrangement of genes or parts of genes. (
  • Throughout evolution, the acquisition of 'new' genes and the rearrangement of 'old' ones has been driven by genetic recombination between bacteriphage and bacterial genomes. (
  • Genetic recombination refers to the exchange of genes between twoDNA molecules to form new combinations of genes on achromosome. (
  • Like mutation, genetic recombination contributes to a population„sgenetic diversity, which is … Recombination between genes A and B leads to a reciprocal exchange of genetic information, changing the arrangement of alleles on the chromosomes. (
  • However, with recombination, the mutant allele can be separated from the other genes on that chromosome. (
  • What we end up with is a new combination of genes that didn't exist before and is not identical to either parent's genetic information. (
  • There is thus a clear need for somatic tissues to maintain their genetic integrity in the face of environmental challenges, and two types of interactions have been shown to play important roles in the conservation as well as flexibility of plant genomes: homologous recombination of repeated sequences and silencing of multiplied genes. (
  • This book summarizes current knowledge and working hypotheses about the frequencies and mechanisms of mitochondrial, plastid, nuclear and viral recombination and the inactivation of repeated genes in plants. (
  • When we implemented this lesson, we observed a dramatic increase in student understanding of genetic linkage and how to use molecular markers to map the location of genes. (
  • Calculate the map distance between linked genes using data from genetic crosses, such as gel electrophoresis banding patterns. (
  • Justify conclusions about genetic linkage by describing the information in the data that allows you to determine genes are linked. (
  • Transposition is important in genetic engineering , as other genes can be relocated along with the transposon DNA. (
  • DNA recombination involves the exchange of genetic material either between multiple chromosomes or between different regions of the same chromosome. (
  • The role of recombination during the inheritance of chromosomes was first demonstrated through experiments with maize. (
  • Specifically, in 1931, Barbara McClintock and Harriet Creighton obtained evidence for recombination by physically tracking an unusual knob structure within certain maize chromosomes through multiple genetic crosses. (
  • Recombination may also occur during mitosis in eukaryotes where it ordinarily involves the two sister chromosomes formed after chromosomal replication. (
  • in bacteria with circular dsDNA chromosomes or circular plasmids, the recombination may occur between linear and circular dsDNA templates or between two circular dsDNA templates. (
  • Shown at the top of the figure is the estimated local recombination rate over a 30‐kb region of human chromosomes 20. (
  • During sexual reproduction, chromosomes transmitted via the mother and the father's gametes (egg and sperm) are shuffled to produce a genetic combination unique to each offspring. (
  • During prophase I, nonsister chromatids of homologous chromosomes exchange pieces of genetic material. (
  • The identified trans-acting additive QTL can be utilized to manipulate CO frequency and distribution in the large polyploid wheat genome opening the possibility to improve the efficiency of gene pyramiding and reducing the deleterious genetic load in the low-recombining pericentromeric regions of chromosomes. (
  • A genetic cross was used to construct such a map from 901 markers that fall into 14 inferred linkage groups corresponding to the 14 nuclear chromosomes. (
  • Subtle levels of heterochiasmy within and between chromosomes were remarkably consistent between the populations, suggesting that local departures from sex-equal recombination rates have evolved. (
  • Figure S3 - 1 to 11: High-resolution genetic maps of various chromosomes consisting of add-on markers. (
  • Physical and genetic maps of the 14 P. falciparum chromosomes in the 7G8 × GB4 cross . (
  • Note the elevated recombination activities at chromosome ends, particularly those at ends of chromosomes 2, 3, 4, 8, and 9, which increase the estimate of genome-wide recombination rate. (
  • Scitable Library by Nature Education: Chromosomes and Cytogenetics, "Genetic Recombination," 2008. (
  • This review will focus on how the regulation of crossover recombination events between homologous chromosomes plays a key role in promoting faithful segregation. (
  • Genetic recombination occurs when genetic material is exchanged between two different chromosomes or between different regions within the same chromosome . (
  • It is the mechanism by which viral genetic material is incorporated into bacterial chromosomes. (
  • Branch migration is the second step of genetic recombination, following the exchange of two single strands of DNA between two homologous chromosomes. (
  • With the advent of genome‐wide human genetic data, understanding the role of recombination in determining patterns of genetic diversity is more important than ever before. (
  • 2011. Genome-wide analysis reveals novel molecular features of mouse recombination hotspots. (
  • The genetic architecture of genome-wide recombination rate variation in allopolyploid wheat revealed by nested association mapping. (
  • Using sequence-based genotyping of a wheat nested association mapping (NAM) population of 2,100 recombinant inbred lines created by crossing 29 diverse lines, we mapped QTL affecting the distribution and frequency of 102 000 crossovers (CO). Genome-wide recombination rate variation was mostly defined by rare alleles with small effects together explaining up to 48.6% of variation. (
  • Genetic investigations of malaria require a genome-wide, high-resolution linkage map of Plasmodium falciparum . (
  • We map Quantitative Trait Loci (QTL) influencing genome-wide recombination rate, genome-wide hotspot usage, and locus-specific recombination rate. (
  • We fine-map three QTL and present strong evidence that genetic variants in REC8 and RNF212 influence genome-wide recombination rate, while genetic variants in PRDM9 influence genome-wide hotspot usage. (
  • Genome-wide recombination rate (GRR) is characterized by considerable inter-individual variation, which is in part inherited [7] - [10] . (
  • Genome-wide levels of cross-over interference were also suggested to differ between individuals [26] , [27] , but corresponding genetic variants - if existing - have not been identified thus far. (
  • We herein describe our efforts to take advantage of (i) the large multigenerational half-sib pedigrees typifying dairy cattle population and (ii) the systematization of genome-wide SNP genotyping with ∼50 K medium density arrays for "genomic selection" purposes [28] , to quantify inter-individual variation in recombination phenotypes as well as to map contributing genetic loci. (
  • We constructed six breed- and sex-specific genome-wide recombination maps using 58,982 autosomal SNPs for two sexes in the three dairy cattle breeds. (
  • The observed population structure, estimated from the five short X chromosomal segments, supports genome-wide frequency-based analyses: African populations show higher genetic diversity, and the general trend of shared variation is seen across the globe from Africa through Middle East, Europe, Central Asia, Southeast Asia, and East Asia in broad patterns. (
  • Although it is a classical genetics topic, genetic linkage remains an important concept to understand in order to grasp modern genetics research approaches including Single Nucleotide Polymorphism (SNP) mapping, Genome Wide Association Studies (GWAS), and gene discovery. (
  • Gene conversion - the process during which homologous sequences are made identical also falls under genetic recombination. (
  • Selfish DNA sequences known as transposons-repetitive genetic elements that do not seem to have benefits to their hosts-are distributed throughout the genome. (
  • Recombination involves the cutting and covalent joining of DNA sequences. (
  • Site-specific recombination occurs at particular DNA sequences recognized by enzymes that recognize that DNA sequence and catalyze recombination with a specific recipient DNA. (
  • Homologous recombination (sometimes called general recombination) occurs between DNA sequences that are homologous -- that is, the two DNA sequences are nearly identical. (
  • Hudson RR and Kaplan NL (1985) Statistical properties of the number of recombination events in the history of a sample of DNA sequences. (
  • Second, we will examine the role of MMR proteins in repressing homeologous recombination, i.e. recombination between divergent sequences. (
  • Mismatch repair stabilizes the cellular genome by correcting DNA replication errors and by blocking recombination events between divergent DNA sequences. (
  • Paradoxically, the satellite arrays bear abundant signatures of recombination, which must occur in order to generate these heavily duplicated sequences. (
  • Using whole-genome sequences, we examined the genetic divergence in Xanthomonas campestris that infected Brassicaceae, and X. citri , pathogenic to a wider host range. (
  • Comparison of phylogenies and divergence of complete genome sequences of CVA6 identified recombination breakpoints in 2A-2C, within VP3, and between 5′ untranslated region and VP1. (
  • Homologous recombination is restricted to sequences of low divergence. (
  • This is attributed to the mismatch repairing system (MMR), which does not allow recombination between sequences that are highly divergent. (
  • This acts as a safeguard against recombination between non-homologous sequences that could result in genome imbalance. (
  • Upon fertilization, a different recombination process blends the homologous sequences from the sperm and egg chromosome, and then creates an offspring with the combined DNA. (
  • Recombination between DNA sequences that contain no sequence homology , also referred to as nonhomologous end joining . (
  • However, the flanking sequences on either side of attP are very important since they contain the binding sites for a number of other proteins Puedes cambiar tus preferencias de publicidad en cualquier momento. (
  • Homologous recombination- homologous DNA sequences having nearly the same nucleotide sequences are … Werecently described an efficient in vitro complementa-tion system which was capable of packaging and maturing bacteriophage T7 DNA (1). (
  • 2. The most common form is general recombination, which usually involves a reciprocal exchange of DNA between a pair of DNA sequences.It occurs anywhere on the microbial chromosome and is typified by the exchanges occurring in bacterial transformation, bacterial recombination, and bacterial transduction. (
  • Homologous recombination - homologous DNA sequences having nearly the same nucleotide sequences are exchanged by means of Rec A proteins. (
  • Homologous (general) recombination: As the name implies, this type occurs between DNA molecules of similar sequences. (
  • Often, there will be a degree of similarity between the sequences, but it's not as obvious as it would be in homologous recombinations. (
  • Site-specific recombination: This is observed between particular, very short, sequences, usually containing similarities. (
  • This student-centered interactive lesson and associated post-class problem set teaches genetic linkage through mapping a gene by determining co-segregation of a phenotype with microsatellite sequences revealed by gel electrophoresis banding patterns. (
  • Eight different types were identified, highlighting the local circulation and diversity of EV-A. Comparative genome analysis revealed evidence of frequent recent intra- and intertypic genetic exchanges between the non-capsid sequences of Madagascan EV-A isolates. (
  • The engineering and characterisation of recombinants generated from progenitors belonging to different EV-A types or EV-A71 genogroups with distantly related non-structural sequences indicated a high level of permissiveness for intertypic genetic exchange in EV-A. This permissiveness suggests that the primary viral functions associated with the non-structural sequences have been highly conserved, through the diversification and evolution of the EV-A species. (
  • It also allows sexually reproducing organisms to avoid Muller's ratchet, in which the genomes of an asexual population accumulate genetic deletions in an irreversible manner. (
  • A recent study, published in the journal Molecular Biology and Evolution , evaluated various regions of the chimpanzee and human genomes for genetic recombination frequency by determining the DNA variability (differences) within large populations of both humans and chimpanzees. (
  • To further assess the rhinovirus intra- and interspecies recombination potential, we used artificially induced recombination by cotransfection of 5′-end-deleted and 3′-end-deleted and replication-deficient genomes. (
  • We used engineered chimeric genomes and artificially induced RNA recombination to study experimentally the recombination potential of rhinoviruses and analyze recombination sites. (
  • We report genetic maps for diploid (D) and tetraploid (AtDt) Gossypium genomes composed of sequence-tagged sites (STS) that foster structural, functional, and evolutionary genomic studies. (
  • Homologous recombination is an ubiquitous process that shapes genomes and repairs DNA damage. (
  • All genetic variation-the substrate for evolution-is ultimately due to spontaneous heritable mutations in the genomes of individual germline cells. (
  • The basic steps of recombination can occur in two pathways, according to whether the initial break is single or double stranded. (
  • Because recombination can occur with small probability at any location along chromosome, the frequency of recombination between two locations depends on the distance separating them. (
  • CO recombination is thought to occur by the Double Holliday Junction (DHJ) model, illustrated on the right, above. (
  • Recombination can occur between two different DNA molecules (intermolecular recombination) or between two regions of a single DNA molecule (intramolecular recombination). (
  • In the figure below there is a 10% probability that a recombination event will occur somewhere between the two markers A and B, and a 2% probability that a recombination event will occur somewhere between the markers B and C, but a 25% probability that a recombination event will occur somewhere between the markers A and C. (
  • 1 Genetic recombination is one of the key events that occur during the production of egg and sperm cells, and secular scientists have long thought it to be a major driver of human and ape evolution. (
  • This process of exchanging DNA segments across sister chromatids is called genetic or homologous recombination and does not occur randomly across the genome, but most often occurs in areas called "hotspots. (
  • In the regions of much lower DNA similarity, which occur as differences in gene order, gene content, and other major DNA sequence differences-the recombination rates were much lower. (
  • Large inversions, once they occur in a species and if they are tolerated, will stop recombination. (
  • The researchers also found evidence for interference between crossovers and non-crossovers - a phenomenon previously only known to occur between crossovers - that makes it unlikely for two recombination events to happen in close proximity. (
  • IMPORTANCE Although genetic exchange between pneumococcal strains is known to occur primarily during colonization of the nasopharynx and colonization is associated with biofilm growth, this is the first study to comprehensively investigate transformation in this environment and to analyze the role of environmental and bacterial factors in this process. (
  • While intraspecies recombination is described frequently among non-rhinovirus enteroviruses, it seems to occur more rarely in rhinoviruses. (
  • One of the consequences of this unique feature is that frequent recombination can occur during reverse transcription of the viral genome to generate a hybrid DNA containing portions of the genetic information from each of the copackaged RNAs ( 26 ). (
  • Although recombination can occur through other means, such as DNA recombination, viral RNAs have to be copackaged into the same virus particle in order for retroviral recombination to occur during reverse transcription ( 26 ). (
  • Recombination can also occur between genetically similar viruses that are further apart in sequence identity than those in a viral population. (
  • On rare occasions, recombination can also occur between genetically distinct but distantly related retroviruses to generate a novel chimeric virus. (
  • I-'H - '-'I'.'. {I'v-iiu'I-IIIIJ.IB (What protein is required for homologous recombination to occur? (
  • Genetic Recombination is now more frequently suggested, but they are still trying to figure out exactly how it works, and what causes it to occur. (
  • Having many regulatory steps achieves the goal of allowing some range of events to occur while ensuring that the number of recombination events does not deviate too much to cause improper chromosome segregation or non-disjunction. (
  • Because recombination can occur with small probability at any location along chromosome, the frequency of recombination between two locations depends on their distance. (
  • At this point, further recombination can occur or be stopped. (
  • are the basis of prokaryote genetics and include mutation, transfer of genetic material between organisms and the introduction of such material into that organism by recombination. (
  • Essentials of Genetics - Chapter 8 - Genetic Analysis and Mapping in Bacteria and Bacteriophages. (
  • Petrescu-Mag 2009), birds (Pricop 2009), mammals Chapter Outline Viruses and Bacteria in Genetics The Genetics of Viruses The Genetics of Bacteria Mechanisms of Genetic Exchange in 1.Student-initiated genetics study group to meet Thursdays at 4pm in either Brooks 203 or 204 for problem solving. (
  • Chapter 8 The Genetics of Bacteria and Their Viruses, - Title: Chapter 8 The Genetics of Bacteria and Their Viruses Author: Laurie Russell Last modified by: Jos Carde Created Date: 7/1/2008 5:46:40 PM. Double-strand DNA breaks in bacteria are repaired by the RecBCD pathway of homologous recombination. (
  • Most introductory genetics courses cover genetic linkage, a core concept in the CourseSource genetics learning outcome framework. (
  • Typically, genetic linkage is taught in a very traditional way within our introductory genetics classes. (
  • The existence of this threshold has two important consequences: (1) the linkage cost disappears beyond a recombination value, or in other words, the selected mutations act as if in practice they segregated independently. (
  • 3 Although it's possible that one or more point mutations caused this perceived increase in virulence, recombination seems a likely candidate because of its greater potential for immediate phenotypic change. (
  • Thus, Ku is an essential component of the pathway(s) utilized for the resolution of DNA double-strand breaks induced by either X rays or V(D)J recombination, and mutations in the Ku86 gene are responsible for the phenotype of group 5 cells. (
  • In contrast to most portions of the genome that had nearly equivalent levels of genetic divergence between subspecies as a result of the accumulation of point mutations, 10% of the core genome involving with homologous recombination contributed to the diversification in Xanthomonas , as revealed by the correlation between homologous recombination and genomic divergence. (
  • To our knowledge, these results are the first evidence of a direct and local influence of recombination hotspots on genetic variation and the fate of individual mutations. (
  • Darwinists are slowly backing away from citing mutations as the genetic mechanism of choice that causes novel and more complex traits to arise. (
  • The consequences of point mutations on the biochemical properties of recombination enzymes and on cell phenotypes help refine the molecular mechanisms of action and the biological roles of recombination proteins. (
  • Here we quantify more than 45,000 genetic interactions between the same 87 pairs of mutations across more than 500 closely related genotypes of a yeast tRNA. (
  • Fig. 2: All single mutations switch sign from detrimental to beneficial in different genetic backgrounds. (
  • Fig. 3: Genetic interactions between all pairs of mutations switch from positive to negative epistasis in different genetic backgrounds. (
  • Genetic recombination and recombinational DNA repair also occurs in bacteria and archaea, which use asexual reproduction. (
  • Bacterial recombination In Bacteria there are: regular bacterial recombination, as well as noneffective transfer of genetic material, expressed as unsuccessful transfer or abortive transfer which is any bacterial DNA transfer of the donor cell recipients who have set the incoming DNA as part of the genetic material of the recipient. (
  • Understanding recombination in bacteria and in viruses that infect bacteria. (
  • In most bacteria with a circular chromosome, such a recombination event would be lethal because the chromosome could not replicate properly and it would be ultimately degraded by DNA exonucleases. (
  • Transformation of genetic material between bacteria was first observed in the 1920s using Streptococcus pneumoniae as a model organism. (
  • In addition, we show that dual-strain carriage in vivo and biofilms formed in vitro can be transformed during colonization to increase their pneumococcal fitness and also, importantly, that bacteria with lower colonization ability can be protected by strains with higher colonization efficiency, a process unrelated to genetic exchange. (
  • Given the high level of conservation of key proteins like RecA and the conservation of the principles of action of all recombination proteins, the deep knowledge acquired during decades of studies of homologous recombination in bacteria is the foundation of our present understanding of the processes that govern genome stability and evolution in all living organisms. (
  • In this process, a small fragment of bacterial DNA is incorporated into an attacking bacteriophage (i.e., virus which infect bacteria) and when this bacteriophage infects a new bacterial cell, it transfers the genetic material into it, and thus genetic recombination takes place. (
  • A. Genetic recombination in bacteria In their classic experiment, Lederberg and Tatum used two different auxotrophic bacterial strains. (
  • eleven Timmy depressurizes her caddy denigrate genetic recombination in bacteria ppt implacably? (
  • genetic recombination in bacteria ppt Zyrian genetically modified organisms in our food supply and self-harming Randolph coruscates his hawsed or witch obliquely. (
  • chiseled and racing Reynolds willy genetic recombination in bacteria ppt her miscomputations invaginated or larks unintentionally. (
  • round-backed genetic recombination in bacteria ppt Broderic pannings his supinating showmanly. (
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  • Recombination in bacteria Si continúas navegando por ese sitio web, aceptas el uso de cookies. (
  • Phage mediated genetic recombination in bacteria i.e. (
  • 1. an overview of bacterial recombination).The three main mechanisms by which bacteria acquire new DNA are transformation, conjugation, and transduction. (
  • Genetic recombination in bacteria: Transformation, Transduction and Conjugation. (
  • Importantly, bacteria-mediated viral co-infection had functional consequences: bacteria that induced viral co-infection facilitated fitness restoration through genetic recombination, with progeny viruses able to replicate under conditions where parental viruses could not. (
  • Bacterial recombination is a type of genetic recombination in bacteria characterized by DNA transfer from one organism called donor to another organism as recipient. (
  • You might imagine the inherent genetic dilemma in a population of organisms that are only capable of dividing asexually, through binary fission, as bacteria do. (
  • The following discussion refers to homologous recombination (we will talk about site-specific recombination later). (
  • 1993. Two related recombinases are required for site-specific recombination at dif and cer in E. coli K12. (
  • Site-specific recombination promoted by a short DNA segment of plasmid R1 and by a homologous segment in the terminus region of the Escherichia coli chromosome. (
  • 2003. Decatenation of DNA circles by FtsK-dependent Xer site-specific recombination. (
  • In conservative site-specific recombination , a mobile DNA element is inserted into a strand of DNA by means similar to that seen in crossover. (
  • Another form of site-specific recombination, transpositional recombination does not require an identical strand of DNA in the mobile element to match with the target DNA. (
  • Pandya Dilip Site-specific recombination requires a special enzymatic machinery, basically one enzyme or enzyme system for each particular site. (
  • Site specific recombination typically occurs in prokaryotes. (
  • As in eukaryotes, recombination also plays important roles in DNA repair and replication in prokaryotic organisms. (
  • This study offers broader implications on what gene clusters (including those involved with metabolism or supplementary metabolite creation) are constructed and taken care of and explains how recombination can be distorted in sex-determining areas in eukaryotes. (
  • One is that it evolved from prokaryotic sex ( bacterial recombination ) as eukaryotes evolved from prokaryotes. (
  • For example, the rapid reshuffling of genetic information possible with transposition enables immunocytes to manufacture the millions of different antibodies required to protect eukaryotes from infection. (
  • Shuffling combinations of alleles through recombination generates the diversity upon which natural selection acts. (
  • Hotspots of recombination are now known to be a key component in dictating the structure of diversity in human populations, and recent research suggests they may play a more fundamental role in the evolution of the human genome. (
  • The relationship between the local recombination rate and patterns of genetic diversity. (
  • Non-crossovers are minute events with a subtler effect than the exchange of larger fragments, but both types of recombination can increase genetic diversity and explain why organisms of the same species differ in many ways. (
  • New work from a multidisciplinary team of scientists used massive DNA sequencing of bacterial populations that grow in the hot springs in Yellowstone National Park to determine their genetic diversity and explore the underlying evolutionary dynamics. (
  • Although we may never definitively know the relative contribution of recombination in creating PRRSV diversity, the possibility that it plays an important role is an inviting concept for several reasons. (
  • Evidence that recombination in mosquitoes is the principal cause of this diversity is two-fold. (
  • We have analyzed human genetic diversity in 33 Old World populations including 23 populations obtained through Genographic Project studies. (
  • The influence of recombination on human genetic diversity. (
  • We introduce three innovations to the analysis of recombination and diversity: fine-scale genetic maps estimated from genotype experiments that identify recombination hotspots at the kilobase scale, analysis of an entire human chromosome, and the use of wavelet techniques to identify correlations acting at different scales. (
  • We show that recombination influences genetic diversity only at the level of recombination hotspots. (
  • Broad-scale association between recombination and diversity is explained through covariance of both factors with base composition. (
  • Unlike most essential cellular processes, recombination events must differ between individuals to maintain genetic diversity. (
  • Recombination increases the genetic diversity in sexually reproducing organisms and can allow an organism to function in new ways. (
  • But when its mechanisms for genetic recombination are incredibly simple, how is a population expected to produce enough genetic diversity to survive such an environmental stressor? (
  • Here, we analyse the extant genomic diversity of SARS-CoV-2 and show that, to date, there is no detectable hallmark of recombination. (
  • It is thought that perhaps recombination occurred in chimpanzees dually infected with SIV that infects red-capped mangabeys and SIV that infects greater spot-nosed monkeys to generate a novel chimeric virus, SIVcpz. (
  • Adam Auton and colleagues Auton:2012 sequenced a panel of chimpanzees to examine recombination in that species, thereby constructing a chimp-specific genetic. (
  • 1 Evolutionists commonly try to buttress their claim of a universal tree of life by pointing to the genetic similarity between chimpanzees and humans. (
  • The first method is to count the number of fixed genetic changes between humans and another species, such as chimpanzees [ 4 ]. (
  • In: Grell R.F. (eds) Mechanisms in Recombination. (
  • However, it requires means to overcome the cellular mechanisms that normally restrict recombination to dif sites harbored by a chromosome dimer and, in the case of integrative mobile elements, to convert dedicated tyrosine resolvases into integrases. (
  • The long-term objective of this project is to define the roles and mechanisms by which the RecQ DNA helicases regulate mitotic recombination and suppress mitotic crossover. (
  • This conference brings together the principal investigators studying the mechanisms of recombination with the goal of further understanding how recombination contributes to genome stability. (
  • This thesis focuses on determining the function of Orf in phage and bacterial recombination pathways by analysing its impact on recombinases encoded by λ and E. coli. (
  • Experiments revealed that Orf interacts with bacterial and phage recombination proteins in the initial exchange step of recombination, modulating the activities of both Exo and RecA. (
  • Significantly, this would direct recombination down the bacterial RecA pathway of break restoration rather than the phage Red pathway with potentially important consequences for the outcome of the exchange reaction. (
  • Much of our understanding of recombination stems from pioneering studies of bacterial and eukaryotic systems such as Escherichia coli and Saccharomyces cerevisiae . (
  • Bacterial speciation usually takes place with lasting homologous recombination, which not only acts as a cohering force between diverging lineages but brings advantageous alleles favored by natural selection, and results in ecologically distinct species, e.g., frequent host shift in Xanthomonas pathogenic to various plants. (
  • Another GENETIC RECOMBINATION IN BACTERIOPHAGE 59 early manifestation of infection is the dispersion of the host DNA, wherein bacterial DNA, normally concentrated in a few compact bodies, becomes largely dispersed and tends to migrate toward the periphery of the host cell (43).Bacterial RNA synthesis ceases and phage "messenger" RNA synthesis (and turnover) soon commences (44-46). (
  • The event is site-specific, as the incorporation (integration) of viral genetic material occurs at a specific location on the bacterial genome, called the attachment site, which is homologous with the phage genome. (
  • Recombination results in a new arrangement of maternal and paternal alleles on the same chromosome. (
  • Recombination can shuffle our allele combinations so that one chromosome can end up with the good A and B alleles together, while the other can get the bad A and B alleles together. (
  • Recombination and haplotype structure over a 3‐Mb region of human chromosome 20. (
  • In a different type of recombination, called non-crossover, a small piece of DNA is copied from one chromosome onto the other without reciprocal exchange leading to gene conversion. (
  • Circles: the replication-recombination-chromosome segregation connection. (
  • 1991. dif, a recA-independent recombination site in the terminus region of the chromosome of Escherichia coli. (
  • Thin grey lines connect the genetic position of each marker (3,184 mSFP and 254 microsatellite markers) with their mapped physical positions on the chromosome. (
  • It is suggested that the data supports the conception of a single linear chromosome in K-12, which fragments randomly during recombination. (
  • Genetic recombination must first begin with genetic segments being able to "recognize" similar genetic segments within the other 'parent' chromosome. (
  • The 2011 Conference on Genetic Recombination and Chromosome Rearrangements will be the fourteenth in a series of highly successful bi-annual conferences devoted to these topics. (
  • 2013. Recombination Rates and Genomic Shuffling in Human and Chimpanzee-A New Twist in the Chromosomal Speciation Theory . (
  • 2012. Genetic recombination is directed away from functional genomic elements in mice . (
  • The first objective of the study was to determine whether the regions with a greater recombination rate experienced a higher genomic adaptation rate. (
  • This asymptote indicates that there is a threshold recombination value beyond which genomic adaptation reaches a maximum. (
  • and reasons for emergence of virulent subtypes are poorly understood because of availability of only limited genomic sequence data and lack of robust cultivation systems and genetic manipulation tools ( 13 ). (
  • In this study, via a comparative genomic analysis, we comprehensively investigated genomic divergence and adaptation in Xanthomonas, and the contributions of host shifts and homologous recombination to the adaptive diversification between species. (
  • Homologous recombination (HR) plays an important role in maintaining genomic integrity. (
  • Recombination also occurs in prokaryotic cells, and it has been especially well characterized in E. coli . (
  • Hence, recombination between two DNA positions that are very close to each other occurs less often than recombination between two DNA positions that are farther apart -- or the further apart two DNA positions are the greater the probability that there will be a recombination event between them. (
  • Because sexual recombination occurs within the mosquito, the relatedness of cotransmitted strains could depend on transmission dynamics, but little is actually known of the factors that influence the relatedness of cotransmitted strains. (
  • However, epidemiological evidence suggests that genetic exchange occurs primarily during pneumococcal nasopharyngeal carriage, which we have recently shown is associated with biofilm growth, and is associated with cocolonization with multiple strains. (
  • nThis animation describes how cloning occurs and how gene is inserted inside a plasmid during recombination process. (
  • Recombination acts to shuffle the existing genetic variation within a population, leading to various approaches for detecting its action and estimating the rate at which it occurs. (
  • This theory of "independent assortment" of alleles is fundamental to genetic inheritance. (
  • Recombination affects the fate of alleles in populations by imposing constraints on the reshuffling of genetic information. (
  • At the population level, recombination affects the rate of creation and loss of haplotypes with cis -configured favorable alleles, placing second order selection pressure on modifiers of global and/or local recombination including inversions [3] . (
  • heterozygosity had not been required for improved recombination, implying that process CALNA2 isn't because of a physical distortion from both non-paired alleles and may also happen during same-sex mating. (
  • It also describes the consequences of such rearrangements, that is, the inheritance of novel combinations of alleles in the offspring that carry recombinant … Instead of replicating its own genetic material, bacterium begins replicating new … Ahora puedes personalizar el nombre de un tablero de recortes para guardar tus recortes. (
  • Explain how recombination can lead to new combinations of linked alleles. (
  • Genetic recombination (also known as genetic reshuffling) is the exchange of genetic material between different organisms which leads to production of offspring with combinations of traits that differ from those found in either parent. (
  • V(D)J recombination in organisms with an adaptive immune system is a type of site-specific genetic recombination that helps immune cells rapidly diversify to recognize and adapt to new pathogens. (
  • Genetic recombination, the process by which sexually reproducing organisms shuffle their genetic material when producing germ cells, leads to offspring with a new genetic make-up and influences the course of evolution. (
  • Components of the recombination apparatus are well described in yeast and C. elegans , but remain largely undefined in most other organisms including mammals [4] , [6] . (
  • In molecular biology "recombination" can also refer to artificial and deliberate recombination of disparate pieces of DNA, often from different organisms, creating what is called recombinant DNA . (
  • Please download the application forms of research proposals, facilities and transporting living modified organisms in and out for genetic recombination experimentation from the Course [email protected] subject "Application forms for Genetic Recombination Experimentation Lecture and Experimentation. (
  • Recombination plays an important role in the control of genetic stability in human as well as all other living organisms. (
  • DNA repair by homologous recombination plays an important role in the control of genetic stability in all living organisms. (
  • Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms and some viruses. (
  • By studying two species of fruit flies, they discovered a gene, MEI-218, that controls the rate of recombination. (
  • An infinite rate of recombination would not increase the adaptive rate of the genome more than a recombination value of 2 cM/Mb (the estimated threshold recombination). (
  • In humans, the rate of recombination, as measured on the megabase scale, is positively associated with the level of genetic variation, as measured at the genic scale. (
  • The frequency of recombination is actually not the same for all gene combinations. (
  • Our map has the highest resolution of recombination events that currently exists for any organism. (
  • We are developing such systems using Haloferax volcanii as a model organism, as it can be cultivated in the laboratory with ease and offers great potential for establishing tractable and informative genetic systems. (
  • Before an organism reproduces it often reshuffles its genetic information. (
  • Genetic recombination - transfer of DNA from one organism (donor) to another recipient. (
  • These gene changes lead to an unexpected genetic recombination that, if the organism survives, increases the genetic variability for the population. (
  • DNA replication vs. homologous recombination. (
  • Homologous recombination helps ensure the timely completion of genome duplication by restarting collapsed replication forks. (
  • However, this beneficial function is not without risk as replication restarted by homologous recombination is prone to template switching (TS) that can generate deleterious genome rearrangements associated with diseases such as cancer. (
  • Replication fork collapse, either with or without DNA breakage, causes a localized cessation of DNA synthesis that can be remedied through the intervention of homologous recombination (HR) proteins, which restart replication. (
  • The markers, map, and recombination parameters are facilitating genome sequence assembly, localization of determinants for such traits as virulence and drug resistance, and genetic studies of parasite field populations. (
  • Walliker, D. , Ranford-Cartwright, L.C. and Babiker, H.A. (1993) Genetic recombination in field populations of Plasmodium falciparum. (
  • Cattle populations in North America count millions, and the dairy industry has genotyped millions of individuals with pedigree information that provide a unique opportunity to study breed-level variations in recombination. (
  • Because split times of species and populations estimated from genetic data are often inversely proportional to the mutation rate, resolving the disagreement would have important implications for understanding human evolution. (
  • According to evolutionary reasoning, the chromosomal areas between humans and chimps that were the most different should have had high levels of genetic recombination that would help explain why they were so different. (
  • Welcome to MOOC-NPTEL course on bioengineering and interface with biology and engineers.In todays class we will study genetic recombination and linkage the production of off springswith combination of traits that differ from those found in either parental generations.Morgan in addition to making contribution for understanding the chromosomal basis ofthe inheritance he was also making many interesting fundamental observations. (
  • One implication of these findings is that at any one moment there will be linked genetic variants, exposed simultaneously to selection in the genome, and therefore selection will be sub-optimal due to the linkage cost. (
  • If linkage cost exists, wherever recombination is low there will be a greater density of selective variants that do not segregate freely, lowering the efficiency of the selection and therefore the adaptation rate. (
  • The results showed a very positive correlation between recombination and adaptation, corroborating the existence of the linkage cost in the genome. (
  • Understanding the genetic basis of these constraints is critical for manipulating the recombination process to improve the resolution of genetic mapping, and reducing the negative effects of linkage drag and deleterious genetic load in breeding. (
  • We identified by linkage disequilibrium and recombination analyses only limited genetic recombination, which occurred exclusively within the 60-kDa glycoprotein gene subtype IbA10G2, a predominant subtype for outbreaks in industrialized nations and a virulent subtype in the study community. (
  • Recombination fraction r, among gene pairs, the likelihood of linkage, L(r), and logarithm of odds (LOD) scores were computed using the statistical relationship of likelihood which assumes a binomial distribution. (
  • Fourth in a series on mutual information and genetic linkage. (
  • We designed a lesson that provides a practical and experimental context to target these common student difficulties in learning about linkage and recombination. (
  • This lesson includes very interactive class sessions and a follow-up problem set and post-test that allows students to develop a deeper understanding of genetic linkage, and provides instructors with insights about student thinking. (
  • Then, describe the following three different forms of prokaryotic genetic recombination: conjugation, transformation, and transduction. (
  • Another method of genetic transfer and recombination is transduction. (
  • Diploids and mitotic recombination. (
  • Mitotic recombination: This doesn't actually happen during mitosis, but during interphase , which is the resting phase between mitotic divisions. (
  • Thus, in mammals, mitotic recombination is highly regulated to prevent excessive crossover. (
  • These studies will provide significant insights into the regulation of mitotic recombination and the origins of the early oncogenic LOH events during carcinogenesis. (
  • Two independent pathways: a Blm-specific pathway and a RecqlS-specific pathway, respectively, are responsible for the restoration of stalled forks via non-recombination-based mechanism to suppress mitotic crossover and reduce cancer risk. (
  • There has been much discussion of the evolutionary role of genetic recombination: the exchange of parental genetic material that gives rise to new genetic combinations in offspring. (
  • Coop G and Przeworski M (2007) An evolutionary view of human recombination. (
  • More recombination equals more evolutionary differences right? (
  • 5 And now this new study has demonstrated that these differences are not due to a mythical evolutionary tinkering and shuffling process associated with genetic recombination, but because humans and chimps were created separately and uniquely. (
  • This work shows that genetic recombination facilitates adaptation and it estimates the evolutionary cost of its absence or depletion in a genome for the first time. (
  • 15.5%), based on real-time reverse transcriptase PCR targeting nucleocapsid (N) gene, were used for further genetic characterization and evolutionary analysis. (
  • Taken together, these finding demonstrate the genetic and evolutionary insights into the currently circulating IBV genotypes in KSA, which could help to better understand the origin, spread, and evolution of infectious bronchitis viruses, and to ascertain the importance of disease monitoring as well as re-evaluation for the currently used vaccines and vaccination programs. (
  • Human-Chimp Genetic Similarity: Is the Evolutionary Dogma Valid? (
  • We investigated the molecular epidemiological processes at work and the contribution of genetic recombination to the evolutionary history of EV-A in Madagascar, focusing on the recently described EV-A71 genogroup F in particular. (
  • The three EV-A71 isolates had different evolutionary histories in terms of recombination, with one isolate displaying a mosaic genome resulting from recent genetic exchanges with Madagascan coxsackieviruses A7 and possibly -A5 and -A10 or common ancestors. (
  • Recombination-mediated rearrangement of variants that arose independently can be of major evolutionary importance. (
  • In addition,λ encodes another recombinase, Orf, which participates in the initial stages of genetic exchange and supplies a frmction equivalent to that of the Escherichia coli RecFOR proteins. (
  • SUMMARY: Further recombination data have been obtained from matings involving different F + auxotrophic mutants of Escherichia coli strain K-12 with the same K-12 F - auxotroph. (
  • Homologous recombination has been most studied and is best understood for Escherichia coli. (
  • Our aim is to approximate the joint-likelihood surface for the recombination and mutation rates, on the basis of all the information contained in the data. (
  • Historically, inference about the recombination and mutation rates has been achieved using summary statistics. (
  • The average similarity of haplotypes carrying the same new (derived) mutation in relation to its frequency in the population and the local recombination rate. (
  • 1 Of course, mutation must also be involved to a considerable extent, because without prior mutational changes, ie, if all existing PRRSV had an identical sequence, recombination might be a moot point. (
  • As a consequence, accurate genetic prediction requires mutation effects to be measured across different genetic backgrounds and the use of higher-order epistatic terms. (
  • DNA-PKcs chemical inhibition versus genetic mutation: Impact on the junctional repair steps of V(D)J recombination. (
  • Instead of an external reference point, we rely on fine-scale knowledge of the human recombination rate to calibrate the long-term mutation rate. (
  • Scientists have long recognized that the exchange of genetic material by crossing over-known as recombination-is vital to natural selection. (
  • They found an unexpectedly high degree of sharing and exchange of genetic material between the tiny, green, photosynthetic cyanobacteria Synechococcus , which are abundant in these scalding, inhospitable environments. (
  • Moreover, research from and claim that coldspots and hotspots might actually reveal the current presence of chromosomal features, such as for example chromatin structures that may affect the availability of DNA towards the recombination equipment [4C6]. (
  • and most basic factor that increases and decreases chromosomal and genetic components. (
  • We conducted sequence analyses of 32 genetic loci of 53 C. hominis specimens isolated from a longitudinally followed cohort of children living in a small community. (
  • Finally, our multiple-breed GWAS found that SNPs in eight loci affected recombination rate and that the PRDM9 gene associated with hotspot usage in multiple cattle breeds, indicating a shared genetic basis for recombination across dairy cattle breeds. (
  • Is the Subject Area "Genetic loci" applicable to this article? (
  • He described several rules of genetic inheritance in his work The genetic law of the Nature (Die genetische Gesätze der Natur, 1819). (
  • Mismatch repair proteins: key regulators of genetic recombination. (
  • We will also compare the requirements for MMR proteins in preventing homeologous recombination to the requirements for these proteins in mismatch repair. (
  • Phageλ encodes its own recombination system, the Red system, comprising Exo, β and γ proteins. (
  • 1 The researchers found that genetic recombination levels were much higher in regions of the genome between humans and chimps where sequence identity was higher. (
  • In this review we aim to compare and contrast the different HCoVs with regard to epidemiology and pathogenesis, in addition to the virus evolution and recombination events which have, on occasion, resulted in outbreaks amongst humans. (
  • The fundamental principles of recombination are likely to be shared between yeast and humans. (
  • by Wendy Gibson, Lori Peacock, Vanessa Ferris, Katrin Fischer, Jennifer Livingstone, James Thomas, Mick Bailey Genetic recombination between pathogens derived from humans and livestock has the potential to create novel pathogen strains, highlighted by the influenza pandemic H1N1/09, which was derived from a re-assortment of swine, avian and human influenza A viruses. (
  • Here we investigated whether genetic recombination between subspecies of the protozoan parasite, Trypanosoma brucei, from humans and animals can generate new strains of human pathogen, T. b. rhodesiense (Tbr) responsible for sleeping sickness (Human African Trypanosomiasis, HAT) in East Africa. (
  • Estimating recombination rates from genetic variation in humans. (
  • Therefore, our study offers insights into the genetic basis of recombination rate variation in wheat and its effect on the distribution of deleterious SNPs across the genome. (
  • Taken together, these studies suggest the existence of genetic basis of recombination that may facilitate a quick response to selection in a short period of time. (
  • Genetic recombination is vital to natural selection, yet some species display far more crossover than others. (
  • Homologous recombination can lead to crossover, which can lead to translocations, deletions, and loss of heterozygosity (LOH), all of which have been implicated as potential cancer causing or - promoting events. (
  • Packaging of the exogenous DNA within the phage head appears to be preceded by recombination of exogenously added DNA with DNA present in the extracts. (
  • Clustering of the sequence motif CCTCCCT within inferred recombination hotspots. (
  • We conducted a comparative population genetic analysis of virulent C. homini s subtype IbA10G2 in children living in a periurban community in Lima, Peru, by multilocus sequence typing (MLST) of 32 genetic markers. (
  • First, recombination would help explain the appreciable differences in genetic sequence among various isolates of PRRSV. (
  • A 3347-locus genetic recombination map of sequence-tagged sites reveals features of genome organization, transmission and evolution of cotton (Gossypium). (
  • The level of recombination was determined by tracking molecular markers for both BC3F6 and F2 generations. (
  • Likewise, recombination between a linear DNA molecule and a circular plasmid would destroy the plasmid. (
  • Perform the positive control recombination with pENTR-Gus plasmid. (
  • The take-home point is that recombination frequencies are directly proportional to distance between two markers. (
  • Three-, four-, and five-factor crosses have shown genetic recombination among the markers, and a five-factor cross is analyzed and discussed. (
  • auscultatory Enrico hassling her debut and may genetic markers for multiple sclerosis floutingly! (
  • Surprisingly, in mammals, Rad52 knockouts showed no significant DNA repair or recombination phenotype. (
  • Spontaneous DNA -PKcs deficiencies in animals result in a severe combined immunodeficiency (SCID) phenotype because DNA -PKcs is required to activate Artemis for V(D)J recombination coding end hairpin opening. (
  • Moreover, the absence of recombination is a key assumption behind the application of phylogenetic inference methods. (
  • Note that although haplotypes often terminate at hotspots of recombination, others do not. (
  • We have investigated the role of chromatin and epigenetic information on recombination, which has revealed hotspots of recombination associated with nucleosome-free regions in gene promoters and terminators. (
  • Comparative studies have shown wide variation in recombination rate among species, but the characterization of recombination features between cattle breeds has not yet been performed. (
  • The potential correlation between recombination rate and fertility, as well as the hypothesized effect of domestication on recombination rates [31] adds to the interest of a detailed characterization of recombination phenotypes in livestock. (
  • Recombination can be artificially induced in laboratory (in vitro) settings, producing recombinant DNA for purposes including vaccine development. (
  • We then mapped the general structures of the recombinant viruses and characterized the recombination junctions by DNA sequencing. (
  • Recombination analysis revealed emergence of two isolates through recombination events resulting in new recombinant viruses. (
  • We've already covered some the consequences of genetic recombination, but in this section we will discuss Recombinant DNA Technology . (
  • Recombination is important-it's not hard to convince anyone of that-but when we look across different species, we see that the rates of crossing over are different," Brand says. (
  • The team focused on two closely related species of fruit flies-Drosophila melanogaster and its sister species, Drosophila mauritiana-because large differences have evolved in their rates of recombination: D. mauritiana does about 1.5 times more crossing over than D. melanogaster. (
  • Since most archaeal species are extremophilic and difficult to cultivate, current knowledge of recombination in the Archaea is confined largely to comparative genomics and biochemistry. (
  • Moreover, they give insight into recombination landscapes and between- species karyotype evolution. (
  • Collectively, our results generated breed- and sex-specific recombination maps for multiple cattle breeds, provided a comprehensive characterization and comparison of recombination patterns between breeds, and expanded our understanding of the breed-level variations in recombination features within an important livestock species. (
  • Sex-specific recombination maps have been generated in several mammalian species with the sex difference in recombination confirmed. (
  • Moreover, because of shared ancestral polymorphism, the time to the most recent common ancestor is always older-and sometimes far older-than the time of species divergence, meaning that split-time calibrations cannot always be directly applied to genetic divergences. (
  • These data provide new insights regarding the mechanism and limitations of rhinovirus recombination. (
  • In the case of some prokaryotes, such as E. coli, there exists a mechanism for genetic recombination known as the sex pillus, which provides a solution for this dilemma. (
  • We introduce a new method for estimating recombination rates from population genetic data. (
  • We confirmed that male recombination map is 10% longer than the female map in all three cattle breeds, consistent with previously reported results in Holstein cattle. (
  • To investigate genetic determinants of novel clinical phenotypes of CVA6, we genetically characterized and analysed CVA6 variants associated with eczema herpeticum in Edinburgh in 2014 and those with aHFMD in CAV isolates collected from 2008. (
  • Genetic determinants for virulence of Cryptosporidium spp. (
  • It was speculated that this intra-genic recombination increased the virulence of the virus resulting in the high death rate associated with this pandemic. (
  • They are hypothesised to be important virulence factors involved with host-pathogen interactions, but their high genetic variability and complexity of analysis means they are typically disregarded in genome studies. (
  • At Waseda University, education and training is mandatory in order to secure the safety of individuals engaged in gene recombination experiments and to prevent diffusion to the surrounding environment. (
  • Individuals engaged in a gene recombination experiment must always attend the "Lecture on Gene Recombination Experiments" on Course [email protected] before beginning the experiment. (
  • Teaching and administrative staff and students who are scheduled to newly begin gene recombination experiments at our school as research activities(Please attend this lecture separately from the advance lecture in experiment subjects. (
  • Along the bottom of the plot is a scaled version of the local recombination landscape, showing peaks of recombination (hotspots). (
  • Jeffreys AJ, Neumann R, Panayi M, Myers S and Donnelly P (2005) Human recombination hot spots hidden in regions of strong marker association. (