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
Author(s): Lu, Dylan; Qian, Haoliang; Wang, Kangwei; Shen, Hao; Wei, Feifei; Jiang, Yunfeng; Fullerton, Eric E; Yu, Paul KL; Liu, Zhaowei | Abstract: Semiconductor quantum well (QW) light-emitting diodes (LEDs) have limited temporal modulation bandwidth of a few hundred MHz due to the long carrier recombination lifetime. Material doping and structure engineering typically leads to incremental change in the carrier recombination rate, whereas the plasmonic-based Purcell effect enables dramatic improvement for modulation frequency beyond the GHz limit. By stacking Ag-Si multilayers, the resulting hyperbolic metamaterials (HMMs) have shown tunability in the plasmonic density of states for enhancing light emission at various wavelengths. Here, nanopatterned Ag-Si multilayer HMMs are utilized for enhancing spontaneous carrier recombination rates in InGaN/GaN QWs. An enhancement of close to 160-fold is achieved in the spontaneous recombination rate across a broadband of working wavelengths accompanied by over
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.
"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 ... Homologous recombination appears to be an important adaptation in hyperthermophiles, such as S. acidocaldarius, for efficiently ... Based on this evidence it appears that Saci-0814 is employed in homologous recombination in S. acidocaldarius and functions as ...
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. ...
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. ...
Genetic Recombination. New York: Wiley ISBN 978-0471102052 Wikimedia Commons has media related to Sordaria fimicola. (Articles ... 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, ...
Lederberg J (1955). "Genetic recombination in bacteria". Science. 122 (3176): 920. Bibcode:1955Sci...122..920L. doi:10.1126/ ... 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". Mutation Research. 12 (3): 269-279. doi:10.1016/0027-5107(71)90015-7. PMID 5563942. Bernstein H ... Schewe MJ, Suzuki DT, Erasmus U (July 1971). "The genetic effects of mitomycin C in Drosophila melanogaster. II. ... Exposure of the fruitfly Drosophila melanogaster to mitomycin C increases recombination during meiosis, a key stage of the ... a condition necessary for the process of natural transformation that transfers DNA and promotes recombination between cells. ...
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 ... Modification of genetic information, Molecular biology, All stub articles, Genetics stubs). ... Cre recombinase Hin recombinase Tre recombinase FLP recombinase Recombinases have a central role in homologous recombination in ...
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 ... "7.3: Linkage Reduces Recombination Frequency". Biology LibreTexts. 2016-06-03. Retrieved 2021-08-28. "Genetic Recombination and ... 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. Palhares, Alessandra ...
Meiosis ordinarily involves genetic recombination. However, male and female hybrids of Australian carp gudgeons (Hypseleotris) ... are fertile, but practice asexual reproduction and display uniparental chromosomal elimination without genetic recombination. ... However, recent genetic research suggests that the carp gudgeons are a cryptic species complex composed of at least four ...
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 ...
... 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 ...
Because of recombination, an individual chromatid can consist of a new combination of maternal and paternal genetic information ... Then each set of homologs pair with each other and exchange genetic information by homologous recombination often leading to ... During this time, homologous chromosomes pair with each other and undergo genetic recombination, a programmed process in which ... 244-45 Cohen PE, Pollack SE, Pollard JW (June 2006). "Genetic analysis of chromosome pairing, recombination, and cell cycle ...
... 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: ...
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. Vol. 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 ...
Recombination - The replicase-transcriptase complex is also capable of genetic recombination when at least two viral genomes ... Su S, Wong G, Shi W, Liu J, Lai AC, Zhou J, Liu W, Bi Y, Gao GF (June 2016). "Epidemiology, Genetic Recombination, and ... RNA recombination appears to be a major driving force in determining genetic variability within a coronavirus species, the ... August 2013). "Genetic characterization of Betacoronavirus lineage C viruses in bats reveals marked sequence divergence in the ...
Genetic recombination can occur when at least two RNA viral genomes are present in the same infected host cell. RNA-RNA ... June 2016). "Epidemiology, Genetic Recombination, and Pathogenesis of Coronaviruses". Trends in Microbiology. 24 (6): 490-502. ... The mechanism of recombination appears to involve template switching during viral genome replication, a process referred to as ... In vivo RNA-RNA recombination of coronavirus in mouse brain. J Virol. 1988 May;62(5):1810-3. PMID 2833625 Su S, Wong G, Shi W, ...
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. ... Recombination in RNA viruses appears to be an adaptation for coping with genome damage. Recombination can occur infrequently ... a form of recombination. Recombination also occurs in the Reoviridae (dsRNA), e.g. reovirus; Orthomyxoviridae ((-)ssRNA), e.g. ...
... (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 ...
Eslava AP, Alvarez MI, Burke PV, Delbrück M (July 1975). "Genetic recombination in sexual crosses of phycomyces". Genetics. 80 ...
In sexual populations, the process of genetic recombination allows the genomes of the offspring to be different from the ... Evolution of sexual reproduction Genetic hitchhiking Hill-Robertson effect Muller HJ (1932). "Some genetic aspects of sex". ... This results in an eventual accumulation of mutations known as genetic load. In theory, the genetic load carried by asexual ... Recombination in the early sexual lineages may have provided a means for coping with genome damage. Muller's ratchet under such ...
Kowalczykowski SC (2000). "Initiation of genetic recombination and recombination-dependent replication". Trends Biochem. Sci. ... Eggleston AK, Mitchell AH, and West SC (1997). "In Vitro Reconstitution of the Late Steps of Genetic Recombination in E. coli ... RuvABC (Recombination UV) is a complex of three proteins that mediate branch migration and resolve the Holliday junction ... "Molecular views of recombination proteins and their control". Nat. Rev. Mol. Cell Biol. 4 (6): 435-45. doi:10.1038/nrm1127. ...
"Genetic control of intrachromosomal recombination in Saccharomyces cerevisiae. I. Isolation and genetic characterization of ... V, D, J recombination can ensure millions of unique B-cell receptors; however, random repair by NHEJ introduces variation which ... Losing genetic stability will favour tumor development, because it favours the generation of mutants that can be selected by ... Genome instability (also genetic instability or genomic instability) refers to a high frequency of mutations within the genome ...
CD4+ TH1 Cells It has been found in both mice and humans that the signature cytokines for these cells is interferon gamma and lymphotoxin alpha. The main cytokine for differentiation into TH1 cells is IL-12 which is produced by dendritic cells in response to the activation of pattern recognition receptors. T-bet is a distinctive transcription factor of TH1 cells. TH1 cells are also characterized by the expression of chemokine receptors which allow their movement to sites of inflammation. The main chemokine receptors on these cells are CXCR3A and CCR5. Epithelial cells and keratinocytes are able to recruit TH1 cells to sights of infection by releasing the chemokines CXCL9, CXCL10 and CXCL11 in response to interferon gamma. Additionally, interferon gamma secreted by these cells seems to be important in downregulating tight junctions in the epithelial barrier.[4] CD8+ TC1 Cells These cells generally produce interferon gamma. Interferon gamma and IL-12 promote differentiation toward TC1 cells. T-bet ...
... in the same gene were often isolated and mapped in a linear order on the basis of recombination frequencies to form a genetic ... suppressive genetic interaction, additive genetic interaction, physical association, and other associations.[74] ... similar to metabolic or genetic/epigenetic networks - that empower the current knowledge on biochemical cascades and molecular ... "A map of directional genetic interactions in a metazoan cell". eLife. 4. doi:10.7554/eLife.05464. PMC 4384530. PMID 25748138 ...
Genetic variability arises from mutations and recombination, while organisms themselves are mobile, leading to geographical ... Genetic speciesEdit. A genetic species as defined by Robert Baker and Robert Bradley is a set of genetically isolated ... Masters, J. C.; Spencer, H. G. (1989). "Why We Need a New Genetic Species Concept". Systematic Zoology. 38 (3): 270-279. doi: ... This is similar to Mayr's Biological Species Concept, but stresses genetic rather than reproductive isolation.[45] In the 21st ...
Second, V(D)J recombination randomly selects one variable (V), one diversity (D), and one joining (J) region for genetic ... To generate each unique antigen receptor, these genes have undergone a process called V(D)J recombination, or combinatorial ... First, somatic hypermutation is a process of accelerated random genetic mutations in the antibody-coding genes, which allows ... This mechanism allows a small number of genetic segments to generate a vast number of different antigen receptors, which are ...
Alternative splicing (the re-combination of different exons) is a major source of genetic diversity in eukaryotes. One ... Many human genetic disorders come from splicing variants.[4] Abnormal splicing variants may also contribute to the development ...
Radding C (1982). "Homologous pairing and strand exchange in genetic recombination". Annu. Rev. Genet. 16 (1): 405-37. doi: ... Sprague G (1991). "Genetic exchange between kingdoms". Curr. Opin. Genet. Dev. 1 (4): 530-3. doi:10.1016/S0959-437X(05)80203-5 ... Orr H (2005). "The genetic theory of adaptation: a brief history". Nat. Rev. Genet. 6 (2): 119-27. doi:10.1038/nrg1523. PMID ... Peters AD, Otto SP (2003). "Liberating genetic variance through sex". BioEssays. 25 (6): 533-7. doi:10.1002/bies.10291. PMID ...
Chapter 27: DNA Replication, Recombination, and Repair *↑ Alberts B; Johnson A; Lewis J; Raff M; Roberts K; Walter P (2002). ... "Bacterial gene transfer by natural genetic transformation in the environment". Microbiol. Rev. 58 (3): 563-602. PMC 372978 ... Chapter 5: DNA Replication, Repair, and Recombination *↑ Tani, Katsuji; Nasu, Masao (2010). "Roles of Extracellular DNA in ...
Before BRAF, the genetic mechanism of melanoma development was unknown and therefore prognosis for patients was poor.[71] ... synthetically lethal with deficiencies in BRCA1 and PALB2 in addition to BRCA2 through RAD51-mediated homologous recombination" ... Cooper DN, Youssoufian H (February 1988). "The CpG dinucleotide and human genetic disease". Hum. Genet. 78 (2): 151-5. doi: ... Cancer is a genetic disease caused by accumulation of DNA mutations and epigenetic alterations leading to unrestrained cell ...
1958 - Joshua Lederberg, United States, for finding out how genetic recombination works in bacteria (transduction (genetics)).[ ... 1983 - Barbara McClintock, United States, for her discovery of mobile genetic elements[74] ... for their finding the genetic controls of organ development and programmed cell death.[93][94] ... for their understanding of the genetic code and its role in protein synthesis.[59] ...
Autoimmune polyendocrine syndrome type 1, is a rare genetic autoimmune syndrome that results from a genetic defect of the ... These distinct receptors are formed by process of V(D)J recombination gene rearrangement stimulated by RAG1 and RAG2 genes.[13] ... Immunodeficiency can be profound.[9] Loss of the thymus at an early age through genetic mutation (as in DiGeorge syndrome, ... Genetic analysis including karyotyping may reveal specific abnormalities that may influence prognosis or treatment, such as the ...
Margulis, Lynn & Sagan, Dorion (1986). Origins of Sex: Three Billion Years of Genetic Recombination (book). 1. Yale University ... UVB causes thymine base pairs next to each other in genetic sequences to bond together into thymine dimers, a disruption in the ... This leads to frameshifting during genetic replication and protein synthesis, usually killing the cell. Before formation of the ... The few that survived had developed enzymes that monitored the genetic material and removed thymine dimers by nucleotide ...
অণুজীবের সবচাইতে আকর্ষণীয় বৈশিষ্ট্য হল এদের অনেক বৈশিষ্ট্য বংশাণুগত পুনঃসংযোজন (জেনেটিক রিকম্বিনেশন, Genetic Recombination) ...
Wei Q, Li L, Chen D (2007). DNA Repair, Genetic Instability, and Cancer. World Scientific. ISBN 978-981-270-014-8. .. [page ... In the final step, there is crossover by means of RecA-dependent homologous recombination.[35] ... Experimental animals with genetic deficiencies in DNA repair often show decreased life span and increased cancer incidence.[15] ... Such alterations are thought to occur early in progression to cancer and to be a likely cause of the genetic instability ...
Multimedia: Genetic recombination. ""(e)tik ...
... s can involve the duplication of large sections of DNA, usually through genetic recombination.[9] These duplications ... Loss of heterozygosity: loss of one allele, either by a deletion or a genetic recombination event, in an organism that ... and the evolution of sex and genetic recombination.[63] DFE can also be tracked by tracking the skewness of the distribution of ... See also: Genetic disorder. If a mutation is present in a germ cell, it can give rise to offspring that carries the mutation in ...
Genetic analysis indicates lower genetic diversity of FIV in the domestic cat compared to wild Felidae species, higher ... where it is reverse transcribed and integrated into the cellular genome through nonhomologous recombination. Once integrated ... Among these subtypes, genetic sequences are mostly conserved; however, wide-ranging genetic differences exist between species ... On the contrary, env, vif, orfa, and rev are the least conserved and exhibit the most genetic diversity among FIV strains.[27] ...
Cytological and molecular genetic studies show that bdelloids evolved from a common ancestor which lost sexual recombination ( ... bdelloid rotifers do engage in genetic (DNA) transfer within a species or clade. The method used is not known at present. ...
This combination is called V(D)J recombination discussed below.[43]. V(D)J recombinationEdit. Further information: V(D)J ... Several complex genetic mechanisms have evolved that allow vertebrate B cells to generate a diverse pool of antibodies from a ... Somatic recombination of immunoglobulins, also known as V(D)J recombination, involves the generation of a unique immunoglobulin ... RAG proteins play an important role with V(D)J recombination in cutting DNA at a particular region.[44] Without the presence of ...
Photon epoch (Big Bang nucleosynthesis, Matter domination, Recombination). *Dark ages *Habitable epoch ... Genetic erosion. *Genetic pollution. Others. *Biodiversity loss *Decline in amphibian populations. *Decline in insect ...
In genetics, a deletion (also called gene deletion, deficiency, or deletion mutation) (sign: Δ) is a mutation (a genetic ... Members of the RAD52 Epistasis Group Contribute to Mitochondrial Homologous Recombination and Double-Strand Break Repair in ... Deletions are responsible for an array of genetic disorders, including some cases of male infertility, two thirds of cases of ... Deletions can be caused by errors in chromosomal crossover during meiosis, which causes several serious genetic diseases. ...
"Prevalence and genetic diversity analysis of human coronaviruses among cross-border children"। Virology Journal (ইংরেজি ভাষায় ... OC43 reveals evolution of different genotypes over time and recent emergence of a novel genotype due to natural recombination" ... "Genetic characterization of Betacoronavirus lineage C viruses in bats reveals marked sequence divergence in the spike protein ...
In addition, a recombination hotspot exists at the ORF1-ORF2 (VP1) junction. Viral replication is cytoplasmic. Entry into the ... Vinjé J, Green J, Lewis DC, Gallimore CI, Brown DW, Koopmans MP (2000). "Genetic polymorphism across regions of the three open ... which can be further divided into different genetic clusters or genotypes. Noroviruses commonly isolated in cases of acute ... rapid and large-scale detection of recombination events among different evolutionary lineages of viral genomes". BMC ...
When recombination does occur in XY chromosomes, it is confined to the tips of the chromosome, leaving most of the genetic ... Recombination generally occurs only when two X chromosomes (XX) pair during female meiosis. Contrastingly, recombination is ... For example, there are two genetic variations that can lead to male sterility in S. latifolia: if it possesses two Y ... they have the potential to increase or decrease in size due to mutation and recombination. In the case of Silene, the pair of ...
This process seems to be dominated by genetic drift resulting from small population size, low recombination rates, and high ... As much as 90% of the genetic material can be lost when a species makes the evolutionary transition from a free-living to an ... Evidence of the deletion of the function of repair and recombination is the loss of the gene recA, gene involved in the ... Wernegreen, J. J.; Moran, N. A. (1999-01-01). "Evidence for genetic drift in endosymbionts (Buchnera): analyses of protein- ...
also showed that UV-irradiation increased the frequency of recombination due to genetic exchange in S. acidocaldarius. Frols et ... Recombination rates exceeded those of uninduced cultures by up to three orders of magnitude. Wood et al. ... Thus it is thought that the ups system in combination with homologous recombination provide a DNA damage response which rescues ... It was proposed that Saci-1497 and Saci-1500 function in an homologous recombination-based DNA repair mechanism that uses ...
"Genetic and epigenetic silencing of microRNA-203 enhances ABL1 and BCR-ABL1 oncogene expression". Cancer Cell. 13 (6): 496-506 ... "Radiation-induced assembly of Rad51 and Rad52 recombination complex requires ATM and c-Abl". J. Biol. Chem. 274 (18): 12748-52 ...
Another was that the virus coat, the protein capsid, is dependent upon the genetic material in the RNA core of the particle and ... "Magnetic field dependence of the geminate recombination of radical ion pairs in polar solvents". Zeitschrift für Physikalische ... This suggests that the genetic material must already be present before the virus can build its coat when reproducing. Such ...
Once, there was thought to be a positive feedback loop at work (a 'Vicious Cycle'); as mitochondrial DNA accumulates genetic ... Unlike nuclear DNA, which is inherited from both parents and in which genes are rearranged in the process of recombination, ... Entities subject to uniparental inheritance and with little to no recombination may be expected to be subject to Muller's ... The rapid mutation rate (in animals) makes mtDNA useful for assessing genetic relationships of individuals or groups within a ...
The effects of natural selection and recombination on genetic diversity in humans : an investigation of Plasmodium falciparum ... Genetic Road Map Drawn for Tracing Route To Common Diseases Video. Profile: Pardis Sabeti. NOVA scienceNOW, 07.02.2008. ... Sabeti developed a family of statistical tests for positive selection that look for common genetic variants found on unusually ...
That is, the severity of clinical signs and symptoms does not correlate with the type of genetic variant. Mutations in the ... RAD51 maintains genome integrity by repairing DNA double-strand breaks through homologous recombination. RAD51 heterozygous ... Experiments in mice also support the claim that CMM disorder is associated with genetic mutations in DCC. Kanga mice, lacking ... Congenital mirror movement disorder (CMM disorder) is a rare genetic neurological disorder which is characterized by mirrored ...
Chromosomes trade parts in a recombination process whose molecular intricacies are now being unraveled ... Before an organism reproduces it often reshuffles its genetic information. ... Genetic Recombination. Before an organism reproduces it often reshuffles its genetic information. Chromosomes trade parts in a ...
A recombination test showed only limited genetic recombination at the gp60 locus. Thus, the high level of LD and limited ... This finding suggested a mixture of ancestral genetic elements and genetic recombination in virulent subtype IbA10G2. This ... We identified by linkage disequilibrium and recombination analyses only limited genetic recombination, which occurred ... Genetic recombination was believed to be rare or nonexistent in C. hominis (17,25,28-30). However, the small number of markers ...
Pontecorvo, G. and Kafer, E. (1958) Genetic analysis based on mitotic recombination. Advances in Genetics, 9, pp. 71-104. (doi ... This chapter illustrates that formal genetic analysis by means of mitotic recombination is perfectly feasible. It leads to the ... mitotic recombination is the only means available so far toward formal genetic analysis and breeding for scientific or applied ... In aspergillus nidulans, which has a sexual cycle and in which the results of genetic analysis based on meiosis are available, ...
Given recombination, if the average frequency of the favored alleles at the various selected loci is equal to p, then the ... Consequently, recombination acts to unblock the adaptive response to multi-locus selection in finite populations. Using ... In the absence of recombination, however, selection will be limited to the highest-fitness genotypes that are already present ... In this paper, we revisit the classic Fisher-Muller models of recombination, taking into account the abundant standing ...
Cre-Lox recombination - Wikipedia [ English. ] * Site-specific DNA recombination in mammalian cells by the Cre recombinase of ... The result of recombination depends on the orientation of the loxP sites. For two lox sites on the same chromosome arm, ... When cells that have loxP sites in their genome express Cre, a recombination event can occur between the loxP sites. The double ... If loxP sites are on different chromosomes it is possible for translocation events to be catalysed by Cre induced recombination ...
... ... we investigated the distribution and structural variation of LTR-RTs in relation to the rates of local genetic recombination ( ... In flowering plants, the accumulation of small deletions through unequal homologous recombination (UR) and illegitimate ... recombination (IR) is proposed to be the major process counteracting genome expansion, which is caused primarily by the ...
... we establish a number of possible correlates of recombination hotspots that help explain general patterns of recombination in ... statistically associated to higher recombination rates in domesticated Criollo. We generated fine-scale recombination maps for ... Mean recombination rates in range between 2.5 and 8.6 cM/Mb for most populations of T. cacao with the exception of the ... We use this map to elucidate the dynamics of recombination rates in distinct populations of the same species, one of which is ...
Frequent recombination events resulted in at least 9 recombinant IA2 alleles, in accordance with the intermingling pattern of ... Moreover, the recombination events detected between the genes and the intermingled phylogenetic pattern indicate that ... The natural barrier of the Yangtze River and heterogeneous balancing selection might help shape the NYR-SYR genetic structure ... Allele frequency analysis across 2 IA loci showed low levels of genetic differentiation among populations on small geographic ...
Questioning the evidence for genetic recombination in the 1918 "Spanish flu" virus. ... Questioning the evidence for genetic recombination in the 1918 "Spanish flu" virus. ...
Genetic Recombination of Bacteria (With Diagram). Article Shared by The following points highlight the three main processes ... Genetic Recombination of Bacteria: 3 Processes. Article Shared by The following points highlight the three main processes ... involved in the genetic recombination of bacteria. The processes are: 1. Conjugation 2. Transformation 3. Transduction. Process ... involved in the genetic recombination of bacteria. The processes are: 1. Conjugation 2. Transformation 3. Transduction. Process ...
Our paper on genetic variation in recombination in the pig just came out the other week. I posted about it already when it was ... Can one breed for increased recombination to improve genetic gain?. Not really. Because recombination breaks up linkage ... Paper: "Genetic variation in recombination rate in the pig". Publicerat i english, genetik av mrtnj ... higher recombination rate could reveal genetic variation for selection and improve genetic gain. However, previous studies ...
The influence of mutation, recombination, population history, and selection on patterns of genetic diversity in Neisseria ... The influence of mutation, recombination, population history, and selection on patterns of genetic diversity in Neisseria ...
Which Three Processes Are Methods of Genetic Recombination ... Which Three Processes Are Methods of Genetic Recombination. How ... Which Three Processes Are Methods of Genetic Recombination August 18, 2022. admin 65 Views ... Although mutual, genetic recombination is a highly circuitous process. It involves the alignment of two. homologous DNA. ... recombination. involves the exchange of genetic material either between multiple chromosomes or between unlike regions of the ...
Kurumizaka H, Mikawa T, Hikiba J, Shibata T. Structural and biochemical aspects of homologous genetic (DNA) recombination. ... Structural and biochemical aspects of homologous genetic (DNA) recombination. In: Seikagaku. 2008 ; Vol. 80, No. 6. pp. 511-520 ... Structural and biochemical aspects of homologous genetic (DNA) recombination. Hitoshi Kurumizaka*, Tsutomu Mikawa, Juri Hikiba ... Structural and biochemical aspects of homologous genetic (DNA) recombination. / Kurumizaka, Hitoshi; Mikawa, Tsutomu; Hikiba, ...
The sequence similarity among specimens of the two dominant outbreak subtypes and genetic recombination in chromosome 6, ... Comparative genomic analysis reveals occurrence of genetic recombination in virulent Cryptosporidium hominis subtypes and ... Comparative genomic analysis reveals occurrence of genetic recombination in virulent Cryptosporidium hominis subtypes and ... Title : Comparative genomic analysis reveals occurrence of genetic recombination in virulent Cryptosporidium hominis subtypes ...
Genetic Recombination and Cryptosporidium hominis Virulent Subtype IbA10G2 Na Li, Lihua Xiao, Vitaliano A. Cama, Ynes Ortega, ... Genetic Recombination and Cryptosporidium hominis Virulent Subtype IbA10G2. ...
Genetic recombination (also known as genetic reshuffling) is the exchange of genetic material between different organisms which ... genetic recombination growth genetic recombination in bacteria pdf prototrophs: synthesize all nutrients... In microorganism ( ... Genetic Analysis of Recombination in Bacteria 358 Isolating Rec" Mutants of E. coli 358 Other Recombination Genes 362 Gene ... Very seldomseparated by genetic recombination is, why it is also important for producing genetic diversity in bacterial.! These ...
... or a defect in the recombination-activating gene (RAG). The genetic defect has not been identified for certain forms of SCID. ... Evaluation of Genetic Tests. In 1999, the National Institutes of Health (NIH)-U.S. Department of Energy Task Force on Genetic ... Genetic Tests and PI Diseases. Advances in molecular biology and genetic technology have facilitated localization of disease ... genetic testing examining a sample of blood or other body fluid or tissue for biochemical, chromosomal, or genetic markers that ...
Recombination Between Endogenous and Exogenous Simian Virus 40 Genes. II. Biochemical Evidence for Genetic Exchange (English) ... Recombination Between Endogenous and Exogenous Simian Virus 40 Genes. II. Biochemical Evidence for Genetic Exchange. scientific ... Recombination between endogenous and exogenous simian virus 40 genes. I. Rescue of a simian virus 40 temperature-sensitive ... Genetic recombinants and heterozygotes derived from endogenous and exogenous avian RNA tumor viruses ...
New findings suggest an explanation for the century-old mystery of how chromosome recombination is regulated during sexual ... Evidence for new theory of genetic recombination. Leave a Comment / Environmental News ... New findings suggest an explanation for the century-old mystery of how chromosome recombination is regulated during sexual ...
recombination protein A. Additional Information & Resources. Tests Listed in the Genetic Testing Registry. *Tests of RAD51 ... Health Conditions Related to Genetic Changes. Congenital mirror movement disorder. At least four RAD51 gene mutations have been ... Insights into DNA recombination from the structure of a RAD51-BRCA2 complex. Nature. 2002 Nov 21;420(6913):287-93. doi: 10.1038 ... By helping repair DNA, these three proteins play a role in maintaining the stability of a cells genetic information. ...
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Genetic recombination instead sexual breeding for the AspergiIlus nidulans. By John McKay , May 9, 2022. 0 Comments ... and results from genetic crossings (see Chapter 3). forty-two. Kafer, Age. (1977). Meiotic and mitotic recombination ... 1. Introduction Genetic analysis is certainly limited by several fungus, especially those that would be without difficulty sex ... Swart, K., P. J. Van der Vondervoort, C. F. B. Witteveen,J. Visser (1990). Genetic localization out of a few family genes ...
... Shcherbak N.L., ... Shcherbak N.L., Belokurova V.B., Komarnitski I.K., Kuchuk N.V. Genetic transformation of Nicotiana africana Merxm. with ... An efficient genetic transformation method for african tobacco Nicotiana africana Merxm. has been established. African tobacco ... plasmids containing lox recombination sites, Tsitol Genet., 2004, vol. 38, no. 4, pp. 3-8.. ...
We show that mutants lacking both enzymes have profound defects in meiotic recombination intermediate metabolism and crossove … ... and indirect studies implicate homologous recombination gone awry as the cause of death. ... Promoter Regions, Genetic / genetics * RecQ Helicases / genetics * RecQ Helicases / metabolism* * Recombination, Genetic / ... Recombination intermediates (joint molecules, JMs) accumulate in these cells, many with structures that are infrequent in wild- ...
SARS-CoV-2 as a product of genetic recombination and purifying selection. ... How does COVID-19 change and what role does recombination play in the changes?. ...
Thermo Fisher Introduces Homologous Recombination Deficiency Score for Cancer Profiling Assay Premium ... Survey Sees Genetic Literacy on the Rise, Though Further Education Needed Survey participants appear to have higher genetic ... Japanese Institute Selects Asperas Server to Support Genetic Data Transfer May 05, 2012 ...
Genetic diversity of T. cruzi. *Experimental recombination. *Recombination in natural populations. *Conclusions and future ... Genetic variation, population structure, and implications for vector control. *Genetic variation and population structure of T ...
... the 1000 Genomes Project aims to build a resource to help to understand the genetic contribution to disease. Here we describe ... By characterizing the geographic and functional spectrum of human genetic variation, ... Analysis of archaic human haplotypes suggests that 5hmC acts as an epigenetic guide for NCO recombination *Bernett Lee ... Recent efforts to map human genetic variation by sequencing exomes1 and whole genomes2,3,4 have characterized the vast majority ...
Detecting Genetic Introgression: High Levels of Intersubspecific Recombination Found in Xylella fastidiosa in Brazil. EUPHRESCO ... 2012): Detecting Genetic Introgression: High Levels of Intersubspecific Recombination Found in Xylella fastidiosa in Brazil. ... only recently after it gained genetic variation via intersubspecific recombination, facilitating a switch from native hosts. A ... plum leaf scald homologous recombination clonal diversity united-states sao-paulo strains sequence bacteria ...
  • Here, we screened for polymorphisms in exons 2 and 3 of the IA1 and IA2 genes in 12 golden pheasant populations across the Chinese mainland to characterize their genetic variation levels, to understand the effects of historical positive selection and recombination in shaping class I diversity, and to investigate the genetic structure of wild golden pheasant populations. (
  • Moreover, the recombination events detected between the genes and the intermingled phylogenetic pattern indicate that interlocus recombination accounts for much of the allelic variation in IA2 . (
  • In several other vertebrates, part of that individual variation in recombination rate (in the gametes passed on by that individual) is genetic, and associated with regions close to known meiosis-genes. (
  • We did not find the hits that they found, and they did not find the hits we found, or any previously known candidate genes for recombination. (
  • In this instance, the issue 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. (
  • Both these genes arelocated within the chromosome W. In the same generation the recessive sex gene was identified withinthe chromosome Z. Objective 7 Genetic recombinationGenetic recombination involves involves combining DNA from 2 different sources into a single molecule. (
  • Genetic Analysis of Recombination in Bacteria 358 Isolating Rec" Mutants of E. coli 358 Other Recombination Genes 362 Gene Conversion and Other Manifestations of Heteroduplex Formation during Recombination 364 SUMMARY 366 QUESTIONS FOR THOUGHT 367 PROBLEMS 367 SUGGESTED READING 368 CHAPTER 11 DNA Repair and Mutagenesis 369 Evidence for DNA Repair 370 Specific … The total nitrogen quantity was determined throughKjeldahl method. (
  • In bacterial genetics, the probability that recombination did not occur between genes is usually determined. (
  • Recombination Between Endogenous and Exogenous Simian Virus 40 Genes. (
  • Genetic localization out of a few family genes impacting glucose oxidase profile inside Aspergillur niger. (
  • Although natural crossover recombination modifier loci have been detected in plants, causal genes have remained. (
  • Recombination or crossing-over produces new combinations of genes due to interchange of corresponding segments between nonsister chromatids of homologous chromosomes, thus, it is an important evolutionary factor. (
  • We found that strains of tetracycline-resistant sequence type 468 GBS have acquired virulence genes from a putative clonal complex 17 GBS donor by recombination. (
  • Simon Boulton added, 'Many cancer cells lose the ability to use homologous recombination, such as when BRCA genes involved in homologous recombination become mutated, and become reliant on repair functions provided by POLQ. (
  • Tightly linked genes show low recombination. (
  • In aspergillus nidulans, which has a sexual cycle and in which the results of genetic analysis based on meiosis are available, mitotic mapping has been compared with, and helped by, meiotic mapping. (
  • Recombination between chromosomes during meiosis leads to shuffling of genetic material between chromosomes, creating new combinations of alleles. (
  • It is believed that recombination in meiosis serves to reshuffle genetic material from both parents to increase genetic variation in the progeny. (
  • During meiosis, homologous chromosomes undergo crossover recombination, which creates genetic diversity and balances homolog segregation. (
  • During meiosis homologous chromosomes undergo crossover recombination. (
  • At the heart of meiosis is crossover recombination, i.e., reciprocal exchange of chromosome fragments between parental genomes. (
  • Surprisingly, in most eukaryotes, including plants, several recombination pathways that can result in crossover event operate in parallel during meiosis. (
  • Genetic recombination is a process of crossover between chromosomes during MEIOSIS (meiosis = a very specialized cell division that creates eggs and sperm for reproduction). (
  • Further, the presence of chiasmata during meiosis in males at a frequency capable of accounting for the observed recombination frequency extends evidence for meiotic origin of recombination in males of D. ananassae. (
  • Results: We demonstrate that recombination is extremely suppressed during meiosis in Sd. (
  • Documenting the role of novel mutation versus homologous recombination in bacterial evolution, and especially in the invasion of new hosts, is central to understanding the long-term dynamics of pathogenic bacteria. (
  • X-linked ichthyosis is a genetic disorder caused by a mutation in the enzyme steroid sulfatase (STS). (
  • Mutation and recombination are primarily responsible for generating the genetic variability in natural populations of microorganisms, plant and animal species including humans. (
  • The mutation for adult polycystic kidney disease (APKD) has previously been localised to chromosome 16 by the demonstration of genetic linkage with the loci for the alpha-chain of haemoglobin and phosphoglycolate phosphatase. (
  • Coronaviruses are single-stranded RNA viruses with some unique characteristics such as the possession of a very large nucleic acid, high infidelity of the RNA-dependent polymerase, and high rate of mutation and recombination in the genome. (
  • If loxP sites are on different chromosomes it is possible for translocation events to be catalysed by Cre induced recombination. (
  • Illustrating that, here is a figure from the paper showing how recombination rate varies along the chromosomes of the pig genome. (
  • Female recombination rate is higher than male recombination rate on most chromosomes, and in particular in regions of higher recombination rate in the middle of certain chromosomes. (
  • DNA recombination involves the exchange of genetic material either between multiple chromosomes or between unlike regions of the aforementioned chromosome. (
  • The part of recombination during the inheritance of chromosomes was first demonstrated through experiments with maize. (
  • Specifically, in 1931, Barbara McClintock and Harriet Creighton obtained bear witness for recombination by physically tracking an unusual knob structure inside certain maize chromosomes through multiple genetic crosses. (
  • Breaks in DNA can be caused by natural and medical radiation or other environmental exposures, and also occur when chromosomes exchange genetic material in preparation for cell division. (
  • instead, a few pieces are traded between nonsister chromosomes in a process called RECOMBINATION. (
  • Genetic maps of the homoeologous group-2 chromosomes were constructed, comprising 114 loci in wheat and 34 loci in rye. (
  • ATR also regulates loading of recombinases RAD51 and DMC1 to DSBs and recombination focus dynamics on synapsed and asynapsed chromosomes. (
  • Background: Intermixing of genomes through meiotic reassortment and recombination of homologous chromosomes is a unifying theme of sexual reproduction in eukaryotic organisms and is considered crucial for their adaptive evolution. (
  • 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. (
  • Given recombination, if the average frequency of the favored alleles at the various selected loci is equal to p, then the expected number of favorable alleles per chromosome will be equal to pL, where L is the number of loci. (
  • Using additional sequencing around these loci, we established that the seven randomly chosen MLST targets contained seven regions of introgression totaling 2,172 bp of 4,161 bp (52%), only 409 bp (10%) of which were detected by other recombination tests. (
  • Clustering of loci in the centromeric regions of the maps, resulting from the concentration of recombination events in the distal chromosomal regions, is observed in wheat and rye, but not in barley. (
  • Furthermore, loci for which homoeoloci can be detected in rye and barley tend to lie in the centromeric regions of the maps, while non-homoeologous and wheat-specific loci tend to be more evenly distributed over the genetic maps. (
  • These studies were carried out, however, on only nine families so that the possibility remained that mutations at other genetic loci might produce the disease. (
  • We find a similar sex difference, with higher recombination in females on all autosomes except chromosome 1 and 13, and a stronger association with GC content in females. (
  • New findings suggest an explanation for the century-old mystery of how chromosome recombination is regulated during sexual reproduction. (
  • These results indicate that Sgs1 and Mus81/Mms4 collaborate to direct meiotic recombination toward interhomolog interactions that promote proper chromosome segregation, and also indicate that Mus81/Mms4 promotes JM resolution in vivo. (
  • Identification of a locus which shows no genetic recombination with the autosomal dominant polycystic kidney disease gene on chromosome 16. (
  • It has twice the genetic material but it is still one chromosome. (
  • Such genetic heterogeneity of linkage would invalidate the general use of chromosome 16 markers for the purposes of detection of the disease, and complicate the characterisation of APKD at the molecular level. (
  • Sep 22, 2022 Telomere vesicles retained the Rad51 recombination factor that enabled telomere fusion with T-cell chromosome ends lengthening them by an average of 3,000 base pairs. (
  • We show that mutants lacking both enzymes have profound defects in meiotic recombination intermediate metabolism and crossover (CO) formation. (
  • Another research area which has been recently established in my lab is genetic control of meiotic recombination in plants. (
  • ludwigii has followed a unique evolutionary trajectory that possibly derives fitness benefits from the combination of frequent mating between products of the same meiotic event with the extreme suppression of meiotic recombination. (
  • This life style ensures preservation of heterozygosity throughout its genome and may enable the species to adapt to its environment and survive with only minimal levels of rare meiotic recombination. (
  • Despite this, nucleotide diversity and population-scaled recombination are positively correlated in eukaryote genomes. (
  • These resources will support ongoing oak genetic improvement efforts and provide insights into the evolution of Quercus and current standing species diversity. (
  • Low genetic diversity may be an Achilles heel of SARS-CoV-2. (
  • In a bi-parental population, only the polymorphisms between the two parents can be queried, whereas in a GWA population the number of polymorphisms is determined by the genetic diversity of the entire germplasm panel. (
  • Little is known about the extent of the genetic diversity and its structuring patterns in protist species living in lakes. (
  • Here, we have investigated the genetic diversity patterns within five dinoflagellate species (Peridinium aciculiferum, Peridinium cinctum, Peridiniopsis borgei, Polarella glacialis, Scrippsiella aff. (
  • In addition, our study shows that protists with identical ITS sequences can harbor considerable amounts of genetic diversity. (
  • We used WGS analysis of 3 ST468 isolates recovered from neonates in Minnesota to test the hypothesis that recombination is a main driver of genetic diversity among serotype IV GBS. (
  • The introduction of diversity into the genetic make-up of cancer cells makes it more likely that harmful characteristics will arise. (
  • They exhibit considerable genetic and host diversity, causing diseases of gastrointestinal and respiratory system in a wide range of vertebrate hosts including humans. (
  • 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 ). (
  • A variety of genomic features have been identified as being associated with regions of high recombination. (
  • iv) an outlook for genetic control in infectious diseases, with special emphasis on the concept of molecular networks that will provide a structure to the huge amount of genomic data. (
  • A strong AT bias of spontaneous mutations and the absence of recombination are likely responsible for its unusually low genomic GC level. (
  • Genomic features and classification of homologous recombination deficient pancreatic ductal adenocarcinoma. (
  • To understand the role of recombination generating and maintaining haplotypic variation in a population, we can construct fine-scale recombination maps. (
  • Here we present a fine-scale recombination map for ten populations of Theobroma cacao - a non-model, long-lived, woody crop. (
  • We generated fine-scale recombination maps for ten populations of Theobroma cacao and used them to understand what processes are associated with population-level variation in this species. (
  • As this study used pedigrees and SNP chips with much coarser density than this, we cannot say much about the fine-scale recombination landscape. (
  • Our results provide support to the hypothesis of increased recombination rates in domesticated plants (Criollo population). (
  • By characterizing the geographic and functional spectrum of human genetic variation, the 1000 Genomes Project aims to build a resource to help to understand the genetic contribution to disease. (
  • Recent efforts to map human genetic variation by sequencing exomes 1 and whole genomes 2 , 3 , 4 have characterized the vast majority of common single nucleotide polymorphisms (SNPs) and many structural variants across the genome. (
  • Reproductive strategies such as sexual reproduction and recombination that involve the shuffling of parental genomes for the production of offspring are ubiquitous in nature. (
  • Using these five genomes and genotyping by sequencing of additional pseudo-F 2 population members, this experimental design enables the exploration of the recombination and inheritance patterns of this variation. (
  • In this paper, we revisit the classic Fisher-Muller models of recombination, taking into account the abundant standing variation that is commonly seen in natural populations. (
  • In the absence of recombination, however, selection will be limited to the highest-fitness genotypes that are already present in the initial population. (
  • 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. (
  • Genetic studies ofAsperg'llus niger: separation of chlorate opposition mutants their include in mitotic mapping and proof to own a 8th linkage category. (
  • Finally, SNP rs224108 on 10q21.2 showed high significance for AD in joint analysis of GWAS and replication study ( P meta = 4.55 × 10 −9 , OR = 1.21), and was confirmed as an independent genetic marker by Linkage disequilibrium calculation and conditional logistic regression analysis. (
  • A study of genetic linkage heterogeneity in adult polycystic kidney disease. (
  • No evidence was found to suggest heterogeneity of genetic linkage between alpha-globin and the APKD locus in this population. (
  • The genome-wide association (GWA) approach represents an alternative to biparental linkage mapping for determining the genetic basis of trait variation. (
  • The genome-wide association (GWA) approach represents an alternative to biparental linkage mapping for the determination of the genetic basis of traits [ 12 ]. (
  • The major advantages of GWA over biparental linkage mapping lie in the much wider variability in phenotype and genotype made accessible, a history of multiple rounds of recombination in many different lineages and the inclusion of germplasm of direct relevance to crop improvement. (
  • Consequently, recombination acts to unblock the adaptive response to multi-locus selection in finite populations. (
  • We use this map to elucidate the dynamics of recombination rates in distinct populations of the same species, one of which is domesticated. (
  • Mean recombination rates in range between 2.5 and 8.6 cM/Mb for most populations of T. cacao with the exception of the domesticated Criollo (525 cM/Mb) and Guianna, a more recently established population (46.5 cM/Mb). (
  • We found little overlap in the location of hotspots of recombination across populations. (
  • We propose a testable mechanistic hypothesis for the change in recombination rate in domesticated populations in the form of mutations to a previously identified recombination-suppressing protein. (
  • In this paper, we estimated recombination rates in nine genotyped pedigree populations of pigs, and used that to perform genome-wide association studies of recombination rate. (
  • Fig 6 from the paper, showing genome-wide association results for eight of the populations (one had too few individuals with recombination rate estimates after filtering for GWAS). (
  • Different populations, where recombinations are estimated independently, also have similar recombination landscapes. (
  • Significance The majority of eukaryotes reproduce sexually, creating genetic variation within populations. (
  • In some cases, our analyses suggested the presence of different genetically homogeneous subgroups (genetic populations) within the same water body. (
  • Thus, it appears that different genetic populations can coexist within the same lake despite the likely occurrence of recombination that tends to homogenize the gene pool. (
  • Adaptation requires genetic variation, but founder populations are generally genetically depleted. (
  • Low genetic and phenotypic variation is common in founder populations, where only one or a few genotypes are isolated from a source population. (
  • In spite of strong genetic bottlenecks, even single colonies with few reproductive individuals suffice to establish stable populations. (
  • We find clear phenotypic differences between the populations and strong correlation between accumulations of TEs ('TE islands') and genetic variation. (
  • Our results suggest that TE islands might function as spring wells for genetic diversification in founder populations of this invasive species. (
  • The heritability of autosomal recombination rate was around 0.07 in females, 0.05 in males. (
  • Autosomal dominant is a pattern of inheritance characteristic of some genetic disorders. (
  • Huntington's disease is an example of an autosomal dominant genetic disorder. (
  • Autosomal recessive is a pattern of inheritance characteristic of some genetic disorders. (
  • Sickle cell anemia is an example of an autosomal recessive genetic disorder. (
  • FA is primarily an autosomal recessive genetic disorder. (
  • therefore, the overall female:male recombination ratio is 0.82:1. (
  • Singh Bashisth N.. Drosophila ananassae: a species characterized by spontaneous male recombination in appreciable frequency. (
  • This unusual phenomenon in D. ananassae is influenced by various genetic factors as well as it shows strain variation as far as frequency of male recombination is concerned. (
  • We find mutations in FIGL-1, a protein shown to downregulate cross-over frequency in Arabidopsis, statistically associated to higher recombination rates in domesticated Criollo. (
  • Pontecorvo, G. and Kafer, E. (1958) Genetic analysis based on mitotic recombination. (
  • This chapter illustrates that formal genetic analysis by means of mitotic recombination is perfectly feasible. (
  • But in other similar organisms, such as aspergillus niger, in which a sexual cycle is unknown, mitotic recombination is the only means available so far toward formal genetic analysis and breeding for scientific or applied purposes. (
  • 1977). Meiotic and mitotic recombination inAspergirrus nidulans and its particular chromosomal aberrations. (
  • Hereditary data according to mitotic recombination. (
  • Frequent recombination events resulted in at least 9 recombinant IA2 alleles, in accordance with the intermingling pattern of the phylogenetic tree. (
  • Under such conditions, reduced effective population size (Ne) should decrease selection efficiency and increase genetic drift, resulting in only weak selection against mildly deleterious alleles which can thus accumulate 2 . (
  • Finally, we establish a number of possible correlates of recombination hotspots that help explain general patterns of recombination in this species. (
  • The importance of recombination hotspots lies in their ability to shuffle genetic variation at higher rates than the rest of the genome, profoundly impacting the dynamics of selection for or against specific mutations [ 1 ]. (
  • In this study, we focus on locally defined recombination hotspots, requiring that their recombination rate be unusually high when compared to neighboring regions. (
  • How about recombination hotspots and PRDM9? (
  • At a very fine scale, most recombination tends to occur in hotspots of around a few kilobasepairs. (
  • 2012 ) found a positive correlation between counts of the PRDM9 DNA-binding motif and recombination rate, which is biologically plausible, as more PRDM9 motifs should mean more hotspots. (
  • Based on MCMC phylogenetic analysis, SimPlot recombination analyses, and intragroup genetic distance, the isolate 007N full-length genome is unique compared to other reported D/E recombinants in Africa. (
  • Although the species has retained an intact meiotic gene repertoire, genetic and population analyses suggest the exceptionally rare occurrence of meiotic crossovers in its genome. (
  • The basic steps of recombination can occur in two pathways, according to whether the initial intermission is single or double stranded. (
  • Homologous recombination in bacteria was originally discovered as a process that not only exchanges genetic material but also provides one of the major pathways of DNA-damage repair. (
  • As part of a collaborative effort to employ molecular genetic technologies in striped bass breeding programs, nearly 500 microsatellite markers were previously developed from repeat-enriched libraries. (
  • These results are discussed in terms of the molecular mechanism of transformational recombination. (
  • Two new studies of RNA viruses are discussed and two new theories suggested that recombination has been favored by selection because of the nature of epistatic interactions are discussed. (
  • Antigenic shifts are probably due to genetic recombination (an exchange of a gene segment) between influenza A viruses that affect humans and/or animals. (
  • The exponential growth of genome sequence information has induced a shift from conventional culture-based to genome-based vaccinology, and allows the tackling of challenges in vaccine development due to pathogen genetic variability. (
  • Novel variants generated by recombination between different HBV genotypes have been documented worldwide and represent an important element of genetic variability with possible clinical implications. (
  • Every bit in eukaryotes, recombination likewise plays important roles in Dna repair and replication in prokaryotic organisms. (
  • When cells that have loxP sites in their genome express Cre, a recombination event can occur between the loxP sites. (
  • Genetic recombination has been shown to occur in Pseudomonas aeruginosa. (
  • The mutations occur as a consequence of the cell's DNA repair machinery, over which the genetic engineer has no control. (
  • Conjugation: In this process, the exchange of genetic mate-rial takes place through a conjugation tube between the two cells of bacteria. (
  • Genetic Programming and Evolvable Machines, 22(4):573-605, 2021. (
  • 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. (
  • For two genetic markers on the same DNA molecule, the closer two genetic markers are to each other, the more often they will be coinherited. (
  • Three additional probes have now been mapped within an existing array of genetic markers flanking this locus. (
  • Genetic maps which reveal the relationships of markers and traits as they are inherited throughout generations are useful to develop modern approaches to improve the efficiency of animal breeding. (
  • These changes and markers of genetic instability are driven by a failure of DNA repair systems and cell cycle regulation. (
  • Genetic grouping of SARS-CoV-2 coronavirus sequences using informative subtype markers for pandemic spread visualization. (
  • In these cases, a sister chromatid serves as the donor of missing fabric via recombination followed past DNA synthesis. (
  • Different regimes of recombination can strongly influence how efficient selection is at purging deleterious mutations and increasing the frequency of beneficial mutations in the population [ 1 ]. (
  • Recombination occurs at very low rate in all these species except for D. ananassae, which shows spontaneous male crossing over in appreciable frequency, which is meiotic in origin. (
  • In 2019, the USPSTF issued updated guidelines on risk assessment, genetic counseling, and genetic testing for BRCA -related cancer in women. (
  • Women with a positive screening result should receive genetic counseling, with further BRCA testing if warranted. (
  • Women without a family history associated with an increased risk for mutations should not receive routine risk assessment, genetic counseling, or BRCA testing. (
  • Without head-to-head comparative data, testing for the presence of BRCA mutations and homologous recombination-deficient (HRD) status remain the optimal ways to select between the PARP inhibitors olaparib (Lynparza), niraparib (Zejula), or rucaparib (Rubraca) for maintenance treatment of patients with ovarian cancer, according to Bobbie J. Rimel, MD. (
  • Olaparib monotherapy for previously treated pancreatic cancer with DNA damage repair genetic alterations other than germline BRCA variants: Findings from 2 phase 2 nonrandomized clinical trials. (
  • Recombination too occurs in prokaryotic cells, and information technology has been especially well characterized in E. coli . (
  • Interestingly, recombination occurs in females of D. melanogaster but not in males. (
  • Recombination between genotypes occurs in regions where multiple genotypes co-circulate and facilitates diversification within individuals and in the general population. (
  • Homologous recombination occurs frequently in GBS and can involve vast areas of the genome in some lineages ( 8 , 9 ). (
  • TEs play a particularly vital role in genome evolution 9 and recurringly generate adaptive phenotypes 10,11,12,13 primarily through (retro-)transposition 14 , and secondarily through ectopic recombination and aberrant transposition 15 . (
  • This process, known as transformational recombination, is dependent in part on the mmsA gene, which encodes a protein having a sequence that is 40% identical to that of the Escherichia coli RecG protein, a junction-specific DNA helicase believed to be involved in the branch migration of recombinational intermediates. (
  • The human bone morphogenet ic protein (rhBMP) developed by genetic engineering, was isolated by Urist, in 1965, and it is considered a substance capable of inducing differentiation of mesenchymal stem cells into osteoblasts, the cells that are responsible for the synthesis of bone matrix. (
  • Recombination plays an important evolutionary role by breaking up haplotypes and shuffling genetic variation. (
  • There is likely a genetic and biochemical heterogeneity of X-linked ichthyosis. (
  • Expanded genome-wide comparisons give novel insights into population structure and genetic heterogeneity of Leishmania tropica complex. (
  • Meiotic cells undergo genetic exchange between homologs through programmed DNA double-strand break (DSB) formation, recombination and synapsis. (
  • Genetic improvement of this species through selective breeding will facilitate progress towards production efficiency. (
  • Depletion of genetic variation is detrimental to species evolution and adaptation 1 . (
  • At the same time, the combination of prolonged inbreeding with severe genetic bottlenecks strongly reduces Ne in this species. (
  • A consensus sequence was extracted from the NGS data and underwent phylogenetic analysis to determine genotype, as well as the recombination pattern. (
  • Genetic determinants for virulence of Cryptosporidium spp. (
  • Genetic transformation of Nicotiana africana Merxm. (
  • An efficient genetic transformation method for african tobacco Nicotiana africana Merxm. (
  • Shcherbak N.L., Belokurova V.B., Komarnitski I.K., Kuchuk N.V. Genetic transformation of Nicotiana africana Merxm. (
  • But as the allele frequencies rise in response to selection the missing genotypes will be generated by recombination. (
  • 1. Some genetic abnormalities, their genotypes and features are distributed in columns A, B and C respectively. (
  • We show that the generation of new genotypic combinations through recombination is an important component of adaptive evolution based on multi-locus selection. (
  • Upon such genetic variations, elemental forces of evolution such as natural selection, random genetic drift and migration operate to bring about micro-evolutionary changes. (
  • ludwigii as an excellent natural forum for the study of genome evolution and recombination rates. (
  • Special Issue: Highlights of Genetic Programming 2020 Events. (
  • Genetic Programming and Evolvable Machines, 21(3):375-397, 2020. (
  • Double-strand DNA breaks in bacteria are repaired by the RecBCD pathway of homologous recombination. (
  • Additionally, recent advances in immunogenetics and genomics should help in the understanding of the influence of genetic factors on the interindividual and interpopulation variations in immune responses to vaccines, and could be useful for developing new vaccine strategies. (
  • By helping repair DNA, these three proteins play a role in maintaining the stability of a cell's genetic information. (
  • FA is the result of a genetic defect in a cluster of proteins responsible for DNA repair via homologous recombination . (
  • Intensive transmission of virulent subtype IbA10G2 in the study area might have resulted in genetic recombination with other subtypes. (
  • Before an organism reproduces it often reshuffles its genetic information. (
  • Regulation must start from consideration of the genetic engineering process used to create the gene-edited organism ("process-based regulation"), so that regulators know where things can go wrong and what to look for. (
  • A total of 68 clonal strains were investigated using Amplified Fragment Length Polymorphism (AFLP), a sensitive genetic fingerprinting technique. (
  • Nonrandom polymorphism distribution suggests recombination. (
  • Genetic recombination is an important source of genome-wide genetic variation fundamental for evolutionary forces like selection and genetic drift to act. (
  • Budding yeast lacking the Sgs1 helicase and the Mus81/Mms4 endonuclease are inviable, and indirect studies implicate homologous recombination gone awry as the cause of death. (
  • To investigate interactions between heterozygosity and recombination we crossed Arabidopsi. (
  • We present the analysis of the genome sequence of MYXV SG33 vaccine strain, which confirms the presence of a large right-end deletion and shows evidence of a field recombination between a wild-type and a vaccine strain. (
  • A codon is a DNA or RNA sequence of three nucleotides (a trinucleotide) that forms a unit of genetic information encoding a particular amino acid. (
  • A significant amount of similarity was identified by comparing the striped bass genetic map with the genome sequence of a model fish, the three-spined stickleback. (
  • Genome sequence-based curation of PubMLST data challenges interspecies recombination in the Burkholderia cepacia complex. (
  • Genome analysis that identified recombination in sequence type (ST) 468 strains of group B Streptococcus . (
  • The major advantages of GWA lie in being able to sample a much wider range of the phenotypic and genotypic variation present, in being able to exploit multiple rounds of historical recombination in many different lineages and to include multiple accessions of direct relevance to crop improvement. (
  • Recombination in bacteria is analogous to gene conversion rather than crossing over in sexually repro-ducing organisms (McVean et al. (
  • MHC class II ß exon 2 variation in pardalotes (Pardalotidae) is shaped by selection, recombination and gene conversion. (
  • however, significant genetic differentiation was observed between pheasants from the northern and southern regions of the Yangtze River. (
  • Furthermore, our data strongly suggest that the virus isolate from which SG33 is derived results from an in vivo recombination between a wild-type South America (Lausanne) strain and a California MSD-derived strain. (
  • Using an artificial gene network model, this work finds that recombination between gene networks imposes selection for genetic robustness, and that negative epistasis evolves as a by-product of this selection. (