Crossing Over, Genetic: 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.Gene Conversion: 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.Meiosis: 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.Recombination, Genetic: 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.Synaptonemal Complex: 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.Chromosomes, Fungal: Structures within the nucleus of fungal cells consisting of or containing DNA, which carry genetic information essential to the cell.Chromosomes: 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)Chromosome Pairing: The alignment of CHROMOSOMES at homologous sequences.Models, Genetic: 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.Crosses, Genetic: 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.DNA, Cruciform: 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.Spores, Fungal: Reproductive bodies produced by fungi.Chromosome Mapping: Any method used for determining the location of and relative distances between genes on a chromosome.Pachytene Stage: The stage in the first meiotic prophase, following ZYGOTENE STAGE, when CROSSING OVER between homologous CHROMOSOMES begins.Chromosome Inversion: 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.Meiotic Prophase I: 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.Mutation: 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.DiethylaminesPlantago: A plant genus of the family Plantaginaceae. The small plants usually have a dense tuft of basal leaves and long, leafless stalks bearing a terminal spike of small flowers. The seeds, known as PSYLLIUM, swell in water and are used as laxatives. The leaves have been used medicinally.Saccharomyces cerevisiae: 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.Diploidy: The chromosomal constitution of cells, in which each type of CHROMOSOME is represented twice. Symbol: 2N or 2X.Alleles: Variant forms of the same gene, occupying the same locus on homologous CHROMOSOMES, and governing the variants in production of the same gene product.Nondisjunction, Genetic: 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.DimethylaminesGenes, Fungal: The functional hereditary units of FUNGI.DNA Repair: 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.Chromatids: 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)Genetic Markers: A phenotypically recognizable genetic trait which can be used to identify a genetic locus, a linkage group, or a recombination event.Heterozygote: An individual having different alleles at one or more loci regarding a specific character.Spermatocytes: 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.L-Aminoadipate-Semialdehyde Dehydrogenase: An enzyme that catalyzes the oxidation of L-2-aminoadipate 6-semialdehyde to L-2-aminoadipate (alpha-aminoadipic acid). It is involved in the biosynthetic pathway of LYSINE.Drosophila melanogaster: A species of fruit fly much used in genetics because of the large size of its chromosomes.X Chromosome: 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.Chromosome Segregation: The orderly segregation of CHROMOSOMES during MEIOSIS or MITOSIS.Saccharomyces cerevisiae Proteins: 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.DNA, Fungal: Deoxyribonucleic acid that makes up the genetic material of fungi.Centromere: 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.Biological Evolution: The process of cumulative change over successive generations through which organisms acquire their distinguishing morphological and physiological characteristics.Molecular Sequence Data: 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.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Prophase: 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.Genetic Linkage: The co-inheritance of two or more non-allelic GENES due to their being located more or less closely on the same CHROMOSOME.Genetic Variation: Genotypic differences observed among individuals in a population.Fungal Proteins: Proteins found in any species of fungus.Drosophila: A genus of small, two-winged flies containing approximately 900 described species. These organisms are the most extensively studied of all genera from the standpoint of genetics and cytology.DNA Breaks, Double-Stranded: Interruptions in the sugar-phosphate backbone of DNA, across both strands adjacently.Base Pair Mismatch: The presence of an uncomplimentary base in double-stranded DNA caused by spontaneous deamination of cytosine or adenine, mismatching during homologous recombination, or errors in DNA replication. Multiple, sequential base pair mismatches lead to formation of heteroduplex DNA; (NUCLEIC ACID HETERODUPLEXES).Evolution, Molecular: The process of cumulative change at the level of DNA; RNA; and PROTEINS, over successive generations.Phenotype: The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.Chromosome Breakage: A type of chromosomal aberration involving DNA BREAKS. Chromosome breakage can result in CHROMOSOMAL TRANSLOCATION; CHROMOSOME INVERSION; or SEQUENCE DELETION.Sister Chromatid Exchange: 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.Mitosis: 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.Selection, Genetic: Differential and non-random reproduction of different genotypes, operating to alter the gene frequencies within a population.Multigene Family: 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)Endodeoxyribonucleases: 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.-.Mosaicism: The occurrence in an individual of two or more cell populations of different chromosomal constitutions, derived from a single ZYGOTE, as opposed to CHIMERISM in which the different cell populations are derived from more than one zygote.Repetitive Sequences, Nucleic Acid: 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).Zea mays: A plant species of the family POACEAE. It is a tall grass grown for its EDIBLE GRAIN, corn, used as food and animal FODDER.Sex Chromosomes: 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)Rad51 Recombinase: A Rec A recombinase found in eukaryotes. Rad51 is involved in DNA REPAIR of double-strand breaks.Heterochromatin: The portion of chromosome material that remains condensed and is transcriptionally inactive during INTERPHASE.Translocation, Genetic: A type of chromosome aberration characterized by CHROMOSOME BREAKAGE and transfer of the broken-off portion to another location, often to a different chromosome.DNA: 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).RecQ Helicases: 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.Genotype: The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.Homozygote: An individual in which both alleles at a given locus are identical.Caenorhabditis elegans: A species of nematode that is widely used in biological, biochemical, and genetic studies.DNA-Binding Proteins: 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.Exodeoxyribonucleases: 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.Species Specificity: 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.Plasmids: 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.Blotting, Southern: 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.Sequence Homology, Nucleic Acid: 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.Telomere: 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.Endonucleases: 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.-.Polymorphism, Genetic: 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.Genes: 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.Genes, Plant: The functional hereditary units of PLANTS.Genome: The genetic complement of an organism, including all of its GENES, as represented in its DNA, or in some cases, its RNA.Schizosaccharomyces: A genus of ascomycetous fungi of the family Schizosaccharomycetaceae, order Schizosaccharomycetales.Mutagenesis: Process of generating a genetic MUTATION. It may occur spontaneously or be induced by MUTAGENS.Restriction Mapping: Use of restriction endonucleases to analyze and generate a physical map of genomes, genes, or other segments of DNA.Gene Deletion: 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.DNA Helicases: 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.DNA Primers: 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.Genetics, Population: 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.Gene Dosage: The number of copies of a given gene present in the cell of an organism. An increase in gene dosage (by GENE DUPLICATION for example) can result in higher levels of gene product formation. GENE DOSAGE COMPENSATION mechanisms result in adjustments to the level GENE EXPRESSION when there are changes or differences in gene dosage.Chromosome Aberrations: Abnormal number or structure of chromosomes. Chromosome aberrations may result in CHROMOSOME DISORDERS.Plants: Multicellular, eukaryotic life forms of kingdom Plantae (sensu lato), comprising the VIRIDIPLANTAE; RHODOPHYTA; and GLAUCOPHYTA; all of which acquired chloroplasts by direct endosymbiosis of CYANOBACTERIA. They are characterized by a mainly photosynthetic mode of nutrition; essentially unlimited growth at localized regions of cell divisions (MERISTEMS); cellulose within cells providing rigidity; the absence of organs of locomotion; absence of nervous and sensory systems; and an alternation of haploid and diploid generations.Gene Duplication: Processes occurring in various organisms by which new genes are copied. Gene duplication may result in a MULTIGENE FAMILY; supergenes or PSEUDOGENES.Drosophila Proteins: Proteins that originate from insect species belonging to the genus DROSOPHILA. The proteins from the most intensely studied species of Drosophila, DROSOPHILA MELANOGASTER, are the subject of much interest in the area of MORPHOGENESIS and development.Cross-Over Studies: Studies comparing two or more treatments or interventions in which the subjects or patients, upon completion of the course of one treatment, are switched to another. In the case of two treatments, A and B, half the subjects are randomly allocated to receive these in the order A, B and half to receive them in the order B, A. A criticism of this design is that effects of the first treatment may carry over into the period when the second is given. (Last, A Dictionary of Epidemiology, 2d ed)Polymorphism, Restriction Fragment Length: 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.Amino Acid Sequence: 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.DNA Damage: 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.Gene Frequency: The proportion of one particular in the total of all ALLELES for one genetic locus in a breeding POPULATION.Cell Cycle Proteins: 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.Ultraviolet Rays: 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.

A genetic linkage map of rat chromosome 9 with a new locus for variant activity of liver aldehyde oxidase. (1/1272)

A genetic linkage map of rat chromosome 9 consisting of five loci including a new biochemical marker representing a genetic variation of the activity of the liver aldehyde oxidase, (Aox) was constructed. Linkage analysis of the five loci among 92 backcross progeny of (WKS/Iar x IS/Iar)F1 x WKS/Iar revealed significant linkages between these loci. Minimizing crossover frequency resulted in the best gene order: Aox-D9Mit4-Gls-Cryg-Tp53l1. The homologues of the Cryg, Gls, and Aox genes have been mapped on mouse chromosome 1 and human chromosome 2q. The present findings provide further evidence for the conservation of synteny among these regions of rat, mouse, and human chromosomes.  (+info)

Removal of one nonhomologous DNA end during gene conversion by a RAD1- and MSH2-independent pathway. (2/1272)

Repair of a double-strand break (DSB) by homologous recombination depends on the invasion of a 3'-ended strand into an intact template sequence to initiate new DNA synthesis. When the end of the invading DNA is not homologous to the donor, the nonhomologous sequences must be removed before new synthesis can begin. In Saccharomyces cerevisiae, the removal of these ends depends on both the nucleotide excision repair endonuclease Rad1p/Rad10p and the mismatch repair proteins Msh2p/Msh3p. In rad1 or msh2 mutants, when both ends of the DSB have nonhomologous ends, repair is reduced approximately 90-fold compared to a plasmid with perfect ends; however, with only one nonhomologous end, repair is reduced on average only 5-fold. These results suggest that yeast has an alternative, but less efficient, way to remove a nonhomologous tail from the second end participating in gene conversion. When the removal of one nonhomologous end is impaired in rad1 and msh2 mutants, there is also a 1-hr delay in the appearance of crossover products of gene conversion, compared to noncrossovers. We interpret these results in terms of the formation and resolution of alternative intermediates of a synthesis-dependent strand annealing mechanism.  (+info)

Distribution of crossing over on mouse synaptonemal complexes using immunofluorescent localization of MLH1 protein. (3/1272)

We have used immunofluorescent localization to examine the distribution of MLH1 (MutL homolog) foci on synaptonemal complexes (SCs) from juvenile male mice. MLH1 is a mismatch repair protein necessary for meiotic recombination in mice, and MLH1 foci have been proposed to mark crossover sites. We present evidence that the number and distribution of MLH1 foci on SCs closely correspond to the number and distribution of chiasmata on diplotene-metaphase I chromosomes. MLH1 foci were typically excluded from SC in centromeric heterochromatin. For SCs with one MLH1 focus, most foci were located near the middle of long SCs, but near the distal end of short SCs. For SCs with two MLH1 foci, the distribution of foci was bimodal regardless of SC length, with most foci located near the proximal and distal ends. The distribution of MLH1 foci indicated interference between foci. We observed a consistent relative distance (percent of SC length in euchromatin) between two foci on SCs of different lengths, suggesting that positive interference between MLH1 foci is a function of relative SC length. The extended length of pachytene SCs, as compared to more condensed diplotene-metaphase I bivalents, makes mapping crossover events and interference distances using MLH1 foci more accurate than using chiasmata.  (+info)

The frequency and allelism of lethal chromosomes in isolated desert populations of Drosophila pseudoobscura. (4/1272)

Second-chromosome lethals were extracted from four populations of Drosophila pseudoobscura in Southern California. Two of the populations were from desert oases and two from the classic habitat on Mt. San Jacinto, previously studied by Dobzhansky. Allelism tests were made on the lethals within and between all locations. The frequency of lethal second-chromosomes in each location was 0.18, and this was not different from the results of other workers for samples throughout the species range. Interpopulational allelism rates were about 0.005, and not different from earlier results of Dobzhansky. Intrapopulational rates in this study were, with one exception, the same as the interpopulational rates, and significantly lower than Dobzhansky found using the third chromosome. This may be due to lethals being linked with heterotic third-chromosome inversions. The allelism rate of the exceptional population (about 0.03 and equal to Dobzhansky's intrapopulational results) may be due to heterotic lethals, or a founder effect. Two lethals were found in three populations each, possibly due to migration among these populations, which are up to 334 km apart.  (+info)

Intermolecular V(D)J recombination is prohibited specifically at the joining step. (5/1272)

V(D)J recombination, normally an intramolecular process, assembles immunoglobulin and T cell receptor genes from V, D, and J coding segments. Oncogenic chromosome translocations can result from aberrant rearrangements, such as occur in intermolecular V(D)J recombination. How this is normally prevented remains unclear; DNA cleavage, joining, or both could be impaired when the recombination signal sequences (RSS) are located in trans, on separate DNA molecules. Here, we show that both trans cleavage and joining of signal ends occur efficiently in vivo. Unexpectedly, trans joining of coding ends is severely impaired (100-to 1000-fold), indicating that protection against intermolecular V(D)J recombination is established at the joining step. These findings suggest a novel surveillance mechanism for eliminating cells containing aberrant V(D)J rearrangements.  (+info)

Genetic recombination of poliovirus in vitro and in vivo: temperature-dependent alteration of crossover sites. (6/1272)

Genetic recombination that occurs with high frequency during poliovirus genome replication is a process whose molecular mechanism is poorly understood. Studies of genetic recombination in a cell-free system in vitro and in infected tissue culture cells in vivo have led to the unexpected observation that temperature strongly influences the loci at which cross-over between the two recombining RNA strands occurs. Specifically, cross-over between two genetically marked RNA strands in vitro and in vivo at 34 degrees C occurred over a wide range of the genome. In contrast, recombination in vivo at 37 and 40 degrees C yielded cross-over patterns that had shifted dramatically to a region encoding nonstructural proteins. Preferential selection of recombinants at 37 and 40 degrees C was ruled out by analyses of the growth kinetics of the recombinants. During the studies of recombination in the cell-free system we found that there is a direct correlation between the ability of a poliovirus RNA molecule to replicate in the cell-free system and its capacity to complement de novo virus synthesis programmed by another viral RNA.  (+info)

Three-dimensional microscopy of the Rad51 recombination protein during meiotic prophase. (7/1272)

An open question in meiosis is whether the Rad51 recombination protein functions solely in meiotic recombination or whether it is also involved in the chromosome homology search. To address this question, we have performed three-dimensional high-resolution immunofluorescence microscopy to visualize native Rad51 structures in maize male meiocytes. Maize has two closely related RAD51 genes that are expressed at low levels in differentiated tissues and at higher levels in mitotic and meiotic tissues. Cells and nuclei were specially fixed and embedded in polyacrylamide to maintain both native chromosome structure and the three dimensionality of the specimens. Analysis of Rad51 in maize meiocytes revealed that when chromosomes condense during leptotene, Rad51 is diffuse within the nucleus. Rad51 foci form on the chromosomes at the beginning of zygotene and rise to approximately 500 per nucleus by mid-zygotene when chromosomes are pairing and synapsing. During chromosome pairing, we consistently found two contiguous Rad51 foci on paired chromosomes. These paired foci may identify the sites where DNA sequence homology is being compared. During pachytene, the number of Rad51 foci drops to seven to 22 per nucleus. This higher number corresponds approximately to the number of chiasmata in maize meiosis. These observations are consistent with a role for Rad51 in the homology search phase of chromosome pairing in addition to its known role in meiotic recombination.  (+info)

Use of a recombination reporter insert to define meiotic recombination domains on chromosome III of Saccharomyces cerevisiae. (8/1272)

In Saccharomyces cerevisiae, meiotic recombination is initiated by DNA double-strand breaks (DSBs). DSBs usually occur in intergenic regions that display nuclease hypersensitivity in digests of chromatin. DSBs are distributed nonuniformly across chromosomes; on chromosome III, DSBs are concentrated in two "hot" regions, one in each chromosome arm. DSBs occur rarely in regions within about 40 kb of each telomere and in an 80-kb region in the center of the chromosome, just to the right of the centromere. We used recombination reporter inserts containing arg4 mutant alleles to show that the "cold" properties of the central DSB-deficient region are imposed on DNA inserted in the region. Cold region inserts display DSB and recombination frequencies that are substantially less than those seen with similar inserts in flanking hot regions. This occurs without apparent change in chromatin structure, as the same pattern and level of DNase I hypersensitivity is seen in chromatin of hot and cold region inserts. These data are consistent with the suggestion that features of higher-order chromosome structure or chromosome dynamics act in a target sequence-independent manner to control where recombination events initiate during meiosis.  (+info)

*Norman Borlaug

... the crossing of genetic barriers; the inability of crops to fulfill all nutritional requirements; the decreased biodiversity ... Backcrossing involves crossing a hybrid and subsequent generations with a recurrent parent. As a result, the genotype of the ... In that time, his group made 6,000 individual crossings of wheat. Initially, Borlaug's work had been concentrated in the ... Food for Thought Norman Borlaug: genetic modification can feed the world, Chron.com, July 13, 2008 Borlaug, N.E. (2000), " ...

*Drosophila melanogaster

... facilitating genetic crossing. The mature larvae has giant chromosomes in the salivary glands called polytene chromosomes-" ... This benefit of genetic diversity is an evolutionary advantage because it increases the chance that some of the offspring will ... Genetic markers are commonly used in Drosophila research, for example within balancer chromosomes or P-element inserts, and ... D. melanogaster was among the first organisms used for genetic analysis, and today it is one of the most widely used and ...

*Genetic recombination

It is the frequency of crossing over between two linked gene loci (markers), and depends on the mutual distance of the genetic ... In eukaryotes, genetic recombination during meiosis can lead to a novel set of genetic information that can be passed on from ... ISBN 978-0-8153-3218-3. "Access Excellence". Crossing-over: Genetic Recombination. The National Health Museum Resource Center. ... The shuffling of genes brought about by genetic recombination produces increased genetic variation. It also allows sexually ...

*C. D. Darlington

He began to make significant contributions to the understanding of the relationship of genetic crossing-over and the ... He developed a keen interest in the Botanic Garden, going on to establish the 'Genetic Garden'. He was also involved in ... Darlington developed a strong interest in the application of genetic insights to the understanding of human history. He ... in which a genetic approach to understanding the behaviour of man was strongly defended. He staunchly defended his colleague in ...

*Claude Cormier

... where his goal was to develop a new flower through genetic crossing. With bachelor's degree in hand, he realized that he was ... This "weaving" results from the conjugation, or crossing, of diverse conceptual, material, and historic elements. As a result, ...

*Triatoma brasiliensis

Costa, J; Almeida, CE; Dujardin, JP; Beard, CB (2003b). "Crossing experiments detect genetic incompatibility among populations ...

*Chromosomal crossover

The linked frequency of crossing over between two gene loci (markers) is the crossing-over value . For fixed set of genetic and ... Chromosomal crossover (or crossing over) is the exchange of genetic material between homologous chromosomes that results in ... 1999). "Modern Genetic Analysis: Mitotic Crossing-Over". New York: W. H. Freeman. Creighton H, McClintock B (1931). "A ... Unequal crossing over Coefficient of coincidence Genetic distance Independent assortment Mitotic crossover Recombinant ...

*Polymorphism (biology)

Evolution of genetic systems, 2nd ed, p120 et seq: The genetic promotion of crossing. Oliver & Boyd, London. Darwin, Charles. ... Since all polymorphism has a genetic basis, genetic polymorphism has a particular meaning: Genetic polymorphism is the ... In genetic polymorphism, the genetic make-up determines the morph. Ants exhibit both types in a single population. Polymorphism ... Genetic polymorphism of serum transferrins in reindeer is used in population and genetic studies. Gene concentrations of ...

*Balancer chromosome

... s can be used as a genetic tool to prevent crossing over (genetic recombination) between homologous ... they also realized that they could limit crossing over in these populations as well give them a very consistent genetic ... Additionally, the genetic marker or markers of the balancer are listed after the name and separated by a comma. Generally ... If crossing over between a balancer chromosome and the balancer's homolog does occur during meiosis each chromatid ends up ...

*Homologous chromosome

Genetic crossing-over, a type of recombintion, occurs during the pachytene stage of prophase I. In addition, another type of ... Genetic variation among organisms helps make a population more stable by providing a wider range of genetic traits for natural ... SDSA recombination does not cause crossing-over. In the process of crossing-over, genes are exchanged by the breaking and union ... genetic recombination (by random segregation) and crossing over produces daughter cells that each contain different ...

*Banksia oblongifolia

Genetic analysis showed generations of crossing and complex ancestry. Morphology generally correlated with genetic profile, but ... occasionally plants that resembled one parent had some degree of genetic hybridisation. Furthermore, there were a few plants ...

*Crossbill

While the direction of crossing seems to be the result of at least 3 genetic factors working together in a case of epistasis ... Edelaar, Pim; Postma, Erik; Knops, Peter; Phillips, Ron (2005). "No support of a genetic basis of mandible crossing direction ... The mechanism by which the bill-crossing (which usually, but not always, occurs in a 1:1 frequency of left-crossing or right- ... Genetic research on their DNA failed to reveal any difference between any of the crossbills (including the morphologically ...

*Mendelian inheritance

Along with crossing over, independent assortment increases genetic diversity by producing novel genetic combinations. There are ... This contributes to the genetic variability of progeny. Mendel's Law of Dominance states that recessive alleles will always be ... However, Mendel's laws stop short of explaining some patterns of genetic inheritance. For most sexually reproducing organisms, ... many violations of independent assortment due to genetic linkage. Of the 46 chromosomes in a normal diploid human cell, half ...

*Non-allelic homologous recombination

During meiosis or mitosis, LCRs can misalign and subsequent crossing-over can result in genetic rearrangement. When non-allelic ... This can give rise to rare genetic disorders, caused by the loss or increased copy number of genes within the deleted or ... Genetic recombination Non-homologous end joining Hurles, Matthew; et al. (2006), "Recombination Hotspots in Nonallelic ... 341-355 Beckmann JS, Estivill X, Antonarakis SE (August 2007). "Copy number variants and genetic traits: closer to the ...

*Barbara McClintock

One of those ideas was the notion of genetic recombination by crossing-over during meiosis-a mechanism by which chromosomes ... as other scientists confirmed the mechanisms of genetic change and genetic regulation that she had demonstrated in her maize ... She remained a regular presence in the Cold Spring Harbor community, and gave talks on mobile genetic elements and the history ... She produced the first genetic map for maize, linking regions of the chromosome to physical traits. She demonstrated the role ...

*Dihybrid cross

... "crossing" their genetic information. The Dihybrid cross is easy to visualize using a Punnett square of dimensions 4 x 4. The ... which occurs by crossing the members of the first filial generation, shows a phenotypic (appearance) ratio of 9:3:3:1, where: ...

*Genetic algorithm

Diversity is important in genetic algorithms (and genetic programming) because crossing over a homogeneous population does not ... These less fit solutions ensure genetic diversity within the genetic pool of the parents and therefore ensure the genetic ... Genetic algorithms are often applied as an approach to solve global optimization problems. As a general rule of thumb genetic ... A typical genetic algorithm requires: a genetic representation of the solution domain, a fitness function to evaluate the ...

*Prophase

... genetic exchange between the non-sister chromatids of the synaptonemal complex in an event known as crossing-over or genetic ... Prophase I the most complex phase in all of meiosis because homologous chromosomes must pair and exchange genetic information. ... In the fourth phase of prophase I, diplotene (from the Greek for "twofold"), crossing-over is completed. Homologous chromosomes ... To ensure pairing of homologous chromosomes and recombination of genetic material occurs properly, there are cellular ...

*Waxy corn

... probably due to years of crossing into various genetic stocks. Only the unique endosperm had been retained. At this time, waxy ... Genetic research of this genetic drift started first with describing (phenotyping) the mutant kernel appearance of maize and ... But the fact that waxy endosperm came to their attention in the first place is probably due to genetic drift. The gene for waxy ... Nelson made a fine structure genetic map of most of these mutations For waxy maize, a single recessive gene (wx) was located on ...

*Chiasma (genetics)

The chiasmata become visible during the diplotene stage of prophase I of meiosis, but the actual "crossing-overs" of genetic ... The phenomenon of genetic chiasmata (chiasmatypie) was discovered and described in 1909 by Frans Alfons Janssens, a Professor ... At a given chiasma, an exchange of genetic material can occur between both chromatids, what is called a chromosomal crossover, ... Sister chromatids also form chiasmata between each other (also known as a chi structure), but because their genetic material is ...

*Synapsis

The crossover of genetic material also provides a possible defence against 'chromosome killer' mechanisms, by removing the ... SDSA recombination does not cause crossing-over. Both the non-crossover and crossover types of recombination function as ... A further consequence of recombinant synapsis is to increase genetic variability within the offspring. Repeated recombination ... "crossing-over". This exchange produces a chiasma, a region that is shaped like an X, where the two chromosomes are physically ...

*Gene

During the process of meiotic cell division, an event called genetic recombination or crossing-over can sometimes occur, in ... The genetic variation in relative frequencies of different alleles in a population is due to both natural selection and genetic ... The related term synthetic biology is sometimes used to refer to extensive genetic engineering of an organism. Genetic ... The genetic code specifies the correspondence during protein translation between codons and amino acids. The genetic code is ...

*Haplogroup

Other chromosomes, autosomes and X chromosomes in women, share their genetic material (called crossing over leading to ... Genetic genealogy Genealogical DNA test List of genetic genealogy topics List of haplogroups of notable people By C. Barry Cox ... In a large population with efficient mixing the rate of genetic drift for common alleles is very low; however, in a very small ... This displays the idea of genetic drift. Human Y chromosome DNA (Y-DNA) haplogroups are named from A to T, and are further ...

*Agroscope

In 1998 an Austrian research team discovered, on the basis of molecular-genetic tests, that the crossing partners were not ... For a long time this vine variety was thought to be a crossing between Riesling and Silvaner. ...

*Outcrossing

Out-crossing or out-breeding is the practice of introducing unrelated genetic material into a breeding line. It increases ... For example, in this context, a recent veterinary medicine study tried to determine the genetic diversity within cat breeds. ... He then used the resulting offspring to chart inheritance patterns, using the crossing of siblings, and backcrossing to parents ... Breeders inbreed within their genetic pool, attempting to maintain desirable traits and to cull those traits that are ...

*Kristine Kochanski

Lister also realises that the in-vitro tube with Kochanski and Lister's genetic information is Lister himself, creating a ... In "Ouroboros" (1997), Kochanski (now played by Chloë Annett) is seen crossing through a linkway originating from a parallel ...
Recombination plays a crucial role in creating novel genetic variation in sexually reproducing species (Barton and Charlesworth 1998; Otto and Lenormand 2002) and for securing proper disjunction of sister chromatids and chromosomes during meiosis. Chiasma interference (hereafter simply referred to as interference) is a fundamental process that influences crossover locations because the formation of a chiasma reduces the chance of a nearby recombination (Sturtevant 1915). Interference was thought to only occur within independent chromosome arms because the centromere acted as a barrier to interference (Mather 1938).. Another important role of recombination includes crossing over between homeologs; these crossovers slow rediploidization of polyploid-origin genomes resulting from recent whole genome duplications (WGD). Pioneering studies considered allozyme loci in lake trout and brook trout hybrids to characterize segregation of duplicated loci in males and presented a meiotic model for explaining ...
Recombination plays a crucial role in creating novel genetic variation in sexually reproducing species (Barton and Charlesworth 1998; Otto and Lenormand 2002) and for securing proper disjunction of sister chromatids and chromosomes during meiosis. Chiasma interference (hereafter simply referred to as interference) is a fundamental process that influences crossover locations because the formation of a chiasma reduces the chance of a nearby recombination (Sturtevant 1915). Interference was thought to only occur within independent chromosome arms because the centromere acted as a barrier to interference (Mather 1938).. Another important role of recombination includes crossing over between homeologs; these crossovers slow rediploidization of polyploid-origin genomes resulting from recent whole genome duplications (WGD). Pioneering studies considered allozyme loci in lake trout and brook trout hybrids to characterize segregation of duplicated loci in males and presented a meiotic model for explaining ...
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, ...
The pairing of homologues at the start of meiosis we helps to ensure that each gamete gets one person in each set. Homologues contact each other along most of their size and are also held together by a protein that is special called the synaptonemal complex. This relationship associated with the homologues may continue from hours to times. The relationship of this two chromosomes is known as a bivalent, and since you can find four chromatids included additionally, it is known as a tetrad. The points of accessory are called chiasmata (single, chiasma).. The pairing of homologues includes the near-identical sequences discovered on each chromosome, and also this sets the phase for crossing over. The mechanism that is exact which crossing over occurs is certainly not understood. Crossing over is controlled by an extremely protein that is large called a recombination nodule. A few of the proteins involved also play roles in DNA replication and fix, which will be unsurprising, given that all three ...
Background: Meiotic recombination is the foundation for genetic variation in natural and artificial populations of eukaryotes. Although genetic maps have been developed for numerous plant species since the late 1980s, few of these maps have provided the necessary resolution needed to investigate the genomic and epigenomic features underlying meiotic crossovers. Results: Using a whole genome sequencing-based approach, we developed two high-density reference-based haplotype maps using diploid potato clones as parents. The vast majority (81%) of meiotic crossovers were mapped to less than 5 kb. The fine-scale accuracy of crossover detection was validated by Sanger sequencing for a subset of ten crossover events. We demonstrate that crossovers reside in genomic regions of "open chromatin", which were identified based on hypersensitivity to DNase I digestion and association with H3K4me3-modified nucleosomes. The genomic regions spanning crossovers were significantly enriched with the Stowaway family ...
A small crossover control study of triclosan- and triclocarban-containing products in humans showed that routine use of these products does not have a significant impact on human oral or gut microbiome composition or on other metabolic markers.
Recombination events have important uses in experimental and medical genetics. They can be used to order and determine distances between loci (chromosome positions) by genetic mapping techniques. Loci that are on the same chromosome are all physically linked to one another, but they can be separated by crossing over. Examining the frequency with which two loci are separated allows a calculation of their distance: The closer they are, the more likely they are to remain together. Multiple comparisons of crossing over among multiple loci allows these loci to be mapped, or placed in relative position to one another.. Recombination frequency in one region of the genome will be influenced by other, nearby recombination events, and these differences can complicate genetic mapping. The term interference describes this phenomenon. In positive interference, the presence of one crossover in a region decreases the probability that another crossover will occur nearby. Negative interference, the opposite of ...
What is the difference between Translocation and Crossing Over? Translocation occurs between non-homologous chromosomes while crossing over occurs between...
Homologous chromosomes do not pair during mitosis, so there is no opportunity for crossing over to occur. Crossing over between non-sister chromatids of homologous chromosomes occurs in meiosis...
One major conclusion from our analysis is that there is a higher rate of nonsynonymous site evolution in the regions of the Drosophila genome that apparently lack crossing over, as compared with regions with low to high rates of crossing over (Figure 1). We also found little evidence of differences in dN or dN/dS between low, intermediate, and high crossover regions. This contrasts with the results of Betancourt and Presgraves [12] and Presgraves [13], who found higher nonsynonymous divergence between D. melanogaster and D. simulans in regions of high recombination when compared with the rest of the genome. The reason for this difference is not entirely clear, but it may reflect the fact that the previous studies were based on relatively few genes. These might have included some genes with unusually high rates of amino acid sequence evolution in the high recombination regions. Consistent with this possibility, Betancourt and Presgraves [12] and Presgraves [13] found a much higher mean ratio of ...
I have a prof that says that crossing over in meiosis happens during metaphase 1. I asked her about this, pointing out the evidence that I had that said that crossing over happens during prophase 1. She says that the line between prophase and metaphase are obscure and that the actual event happens during metaphase. What does anyone have to say about this ...
During meiosis, crossing over occurs during prophase I. It is the exchange of genetic material between homologous chromosomes that results in recombinant chromosomes, which contribute to genetic...
One possible explanation for the less severe meiotic phenotype of the Ercc1X mutant is that the maternal ERCC1 protein deposited during oogenesis may perdure and partially compensate for the lack of ERCC1 protein produced in an Ercc1X mutant. To test this possibility, we measured X nondisjunction in Ercc1X mutants derived from Ercc1X mutant mothers. These maternal/zygotic (m/z) Ercc1X mutants have higher levels of X nondisjunction than zygotic Ercc1X mutants (Table 1), similar to the levels seen in mus312 mutants and in some mei-9 alleles (Yildiz et al. 2002, 2004). Direct measurements of crossing over also show that m/z Ercc1X mutants have a reduction in crossovers similar to zygotic mei-9 mutants; however, we also find that m/z mei-9 mutants have a stronger overall reduction in crossing over than either m/z Ercc1X or zygotic mei-9 mutants (Table 2). This indicates that there may be a maternal effect in mei-9 mutants as well as in Ercc1 mutants. We conclude that a maternal effect does not mask ...
Genetic mapping of genes in eukaryotes is based on the mechanisms leading to new combinations of genes: random assortment of chromosomes and crossing‐over
Get an answer for Between what genes will crossing over most likely occur on a gene map? and find homework help for other Science questions at eNotes
The addition of extra copies of segments of DNA on the same strand by unequal crossing over during meiosis. An explanation for the existence of satellite DNA, which are highly-repeated, non-transcribed sequences of DNA with no clear function. An alternative explanation to saltatory replication ...
Vaccines have been a part of Army life since the Revolutionary War. Today, Soldiers receive a variety of immunizations against infectious diseases to maintain personal readiness and NCOs should emphasize their importance.
The special process of cell division by which part exchange takes place between the non-sister chromatids of homologous chromosomes is known as crossing ov
Greys Anatomy and Station 19 will return in January with a two-hour crossover event, while Station 19 takes over the 8 p.m. slot and Greys moves to 9 p.m.
It is well known that rather general mutation-recombination models can be solved algorithmically (though not in closed form) by means of Haldane linearization. The price to be paid is that one has to work with a multiple tensor product of the state space one started from. Here, we present a relevant subclass of such models, in continuous time, with independent mutation events at the sites, and crossover events between them. It admits a closed solution of the corresponding differential equation on the basis of the original state space, and also closed expressions for the linkage disequilibria, derived by means of Mobius inversion. As an extra benefit, the approach can be extended to a model with selection of additive type across sites. We also derive a necessary and sufficient criterion for the mean fitness to be a Lyapunov function and determine the asymptotic behaviour of the solutions ...
Just as the uncounted dreams of unnumbered dead worlds echo and resonate within the realms of the Great Ring, the Ectosphere seeps into the manifest realms wherever the living spend any amount of time. The collapse of the universe brought about by the Monocrats Mechanisms has exerted a tremendous pressure upon the Ectosphere, forcing it to erupt into the manifest with the slightest provocation, invitation or tiniest crack or fracture. The dead are very restless in Zalchis and they are desperate to make the most of what time remains before everything comes to an end. You will need to learn how to ward off the insinuations and temptations of the Ectosphere or lose more than your mind to the things that prowl at the very sheerest margins of separation between the manifest and what lies beyond. Crossing over between the realms is no longer a difficult task to accomplish, as in the olden days when people tried to communicate with the departed, now it is a terrible thing that erupts forth if one just ...
In the orginal instructions, she uses two sizes of tubing - one that goes directly on the dowel, othe other, a larger size that slips over the first tubing. It is the largest tubing that gets the genes. This allows you to demonstrate things such as crossing over, etc. I skipped the larger tubing, because my classes dont go into that kind of detail. As a result, I could have skipped the tubing altogether and just painted the stripes on the dowels, but I didnt consider that at the time ...
TeachMeFinance.com is an informational website, and should not be used as a substitute for professional medical, legal or financial advice. Information presented at TeachMeFinance.com is provided on an "AS-IS" basis. Please read the disclaimer for details. ...
Author Summary Cell proliferation involves DNA replication followed by a mitotic division, producing two cells with identical genomes. Diploid organisms, which contain two genome copies per cell, also undergo meiosis, where DNA replication followed by two divisions produces haploid gametes, the equivalent sperm and eggs, with a single copy of the genome. During meiosis, the two copies of each chromosome are brought together and connected by recombination intermediates (joint molecules, JMs) at sites of sequence identity. During meiosis, JMs frequently resolve as crossovers, which exchange flanking sequences, and crossovers are required for accurate chromosome segregation. JMs also form during the mitotic cell cycle, but resolve infrequently as crossovers. To understand how JMs resolve during the mitotic cell cycle, we used a property of budding yeast, return to growth (RTG), in which cells exit meiosis and resume the mitotic cell cycle. By returning to growth cells with high levels of JMs, we determined
Mph1 is a member of the conserved FANCM family of DNA motor proteins that play key roles in genome maintenance processes underlying Fanconi anemia, a cancer predisposition syndrome in humans. Here, we identify Mte1 as a novel interactor of the Mph1 helicase in Saccharomyces cerevisiae. In vitro, Mte1 (Mph1-associated telomere maintenance protein 1) binds directly to DNA with a preference for branched molecules such as D loops and fork structures. In addition, Mte1 stimulates the helicase and fork regression activities of Mph1 while inhibiting the ability of Mph1 to dissociate recombination intermediates. Deletion of MTE1 reduces crossover recombination and suppresses the sensitivity of mph1Δ mutant cells to replication stress. Mph1 and Mte1 interdependently colocalize at DNA damage-induced foci and dysfunctional telomeres, and MTE1 deletion results in elongated telomeres. Taken together, our data indicate that Mte1 plays a role in regulation of crossover recombination, response to replication ...
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 ...
Looking for online definition of crossing-over in the Medical Dictionary? crossing-over explanation free. What is crossing-over? Meaning of crossing-over medical term. What does crossing-over mean?
Homologous recombination utilizing hosts own recombination machinery is widely used for genome engineering. More specifically, a plasmid that carries homologous arms to the upstream and downstream areas of target gene(s), is introduced into the host. In order to select for a double crossover event (gene deletion), a positive selection (such as antibiotic resistance cassettes) or combination with a negative selection (such as mazF [84] or pyrE [85]) is used. Other variant methods that rely on homologous recombination also include Allele-Coupled Exchange (ACE) [86], Triple crossover [87] and scar-less, marker-less knockout or knock-in using two negative selection markers (C. thermocellum), detailed information has recently been reviewed [88]. In some instances, specific DNA sequences which can be recognized by site-specific recombinases, flanking the antibiotic resistance cassettes were introduced into the chromosome at the same time during the double crossover event. The antibiotic resistance ...
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Our approach to score meiotic crossovers documents substantial within-species variation for genomewide recombination rates in both outcrossed and inbred plant and animal species and shows that QTL that underlie this variation can be identified. Such variation is likely to be ubiquitous, especially considering that the statistical power to map this trait is not high.. Our data corroborate previous studies of a number of species of plants and animals, which reported existence of strong genetic background effects on the frequency of meiotic recombination (Roberts and Roberts 1921; Rees 1961; Säll 1990; Williams et al. 1995; Koehler et al. 2002; Sanchez-Moran et al. 2002; Anderson et al. 2003). Although most of these studies considered crossover frequencies in specific chromosome intervals, two reports in plants, one in maize (Anderson et al. 2003) and one in Arabidopsis (Sanchez-Moran et al. 2002), indicated significant differences in global recombination rates among several different genotypes. ...
We identify a novel meiotic recombination intermediate, the single-end invasion (SEI), which occurs during the transition from double-strand breaks (DSBs) to double-Holliday junction (dHJs). SEIs are products of strand exchange between one DSB end and its homolog. The structural asymmetry of SEIs indicates that the two ends of a DSB interact with the homolog in temporal succession, via structurally (and thus biochemically) distinct processes. SEIs arise surprisingly late in prophase, concomitant with synaptonemal complex (SC) formation. These and other data imply that SEIs are preceded by nascent DSB-partner intermediates, which then undergo selective differentiation into crossover and noncrossover types, with SC formation and strand exchange as downstream consequences. Late occurrence of strand exchange provides opportunity to reverse recombinational fate even after homologs are coaligned and/or synapsed. This feature can explain crossover suppression between homeologous and structurally heterozygous
During meiosis, crossover recombination is essential to link homologous chromosomes and drive 22 faithful chromosome segregation. Crossover recombination is non-random across the genome, 23 and centromere-proximal crossovers are associated with an increased risk of aneuploidy, 24 including Trisomy 21 in humans. Here, we identify the conserved Ctf19/CCAN kinetochore sub- 25 complex as a major factor that minimizes potentially deleterious centromere-proximal crossovers 26 in budding yeast. We uncover multi-layered suppression of pericentromeric recombination by the 27 ...
The first Nobel laureate who used balancers in his work was Hermann J. Muller. He used a strain of D. melanogaster that was heterozygous for an X-chromosome inversion. This suppresses crossing over between the normal X and the X carrying the inversion during meiosis. A single crossover within the inverted segment will generate a "bridge" at meiosis I, causing the non-crossover chromatid to preferentially segregate to the future ovum. In Mullers work the inverted X was marked with the dominant eye shape mutation, Bar, and carried a recessive lethal allele.1 A female heterozygous for the marked inverted chromosome and a "wild type" chromosome will produce only 1/2 the normal number of male progeny and they will all be wild type. This is because 1/2 the males die because they receive the Bar chromosome and are hemizygous for the lethal. The inversion heterozygosity prevents recombination between the Bar locus and the lethal locus. Muller used this stock, called "ClB", to show that X-irradiation ...
The number of antigenic components detectable in system s such as H-2 in mice depends in part upon technical developments. It is also limited by the number of genetically different individuals available for study and a formula for deducing the number of antigenic components detectable for N unrelated systems is given in the text. If parental types and descendants derived from them by crossing over are included the possibilities are decreased. A new antigenic factor(s) has been brought to light by technical improvements and two more have been revealed by crossing over. Three cross-over combinations H-2g, H-2h and H-2i are now available as homozygotes. A preliminary map gives the order DCVK for genes within the H-2 system. The relative positions of E and K are not yet known but their genes are closely linked. The frequency of recombination between D and K was 1⋅03% for both sexes and 1⋅4% for females. Values obtained by other workers are given in the text. It is concluded that crossing over ...
What is the difference between Bivalent and Chiasmata in Meiosis? Bivalents are associations of homologous chromosomes, and Chiasmata are the junctions where...
Previous studies have suggested that multiple canine 3A forms exist and have distinct metabolic profiles (Ciaccio et al., 1989). The results presented here describe the isolation and initial characterization of a new canine cytochrome P450 3A enzyme, P450 3A26, from a cDNA library generated from PB-induced canine hepatic tissue. The 1.9-kbp cDNA encoding 3A26 exhibited 33 nucleotide and 22 amino acid differences when compared with canine P450 3A12. The sequence identity between CYP3A12 and CYP3A26 at the N-terminal and 5′-untranslated region, and the sequence differences found mostly at the C-terminal and 3′-untranslated region suggest that CYP3A26 might be the product of a recent "gene conversion" or "unequal crossing over" event involving CYP3A12. According to this hypothesis, the 5′ portion of the CYP3A26 gene would be derived from CYP3A12 and the 3′ portion would be derived from either an ancestral CYP3A26 gene, which was subsequently lost, or from a putative third canine CYP 3A ...
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The induction, accumulation, and persistence of sister chromatid exchanges (SCEs) and high SCE frequency cells (HFCs) was measured in peripheral blood lymphocytes of women with breast cancer before chemotherapy and on multiple occasions during and after therapy. Chemotherapy consisted of i.v. infusion of cyclophosphamide, Adriamycin, and 5-fluorouracil, administered on day 1 of each of approximately six 21-day cycles. This treatment resulted in a highly significant induction of SCEs (1.8-fold, P , 0.0001) and HFCs (5-fold, P , 0.0001) measured in samples obtained 1 week after the first therapy. Accumulation of lesions leading to SCEs was measured by comparing samples surrounding the first and last rounds of therapy and was significant for both SCEs and HFCs in most comparisons. Persistence of lesions leading to SCEs was evaluated at multiple times until 9 months after completion of therapy, and both SCEs and HFCs remained significantly elevated throughout this time. Differences between donors ...
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Title: The Darkest Side of Me Author: D.L.SchizoAuthoress Rating: PG-13/R Spoilers: for the Joker - Last Laugh crossover event; timeline is between Nightwing #63 and Nightwing #64 . Warnings: character death, strong language Prompt: DCU, Jason Todd/Dick Grayson, he always hoped Jason would come…
As The CW starts the ramp-up to the four-series crossover event (ARROW, FLASH, SUPERGIRL and LEGENDS OF TOMORROW) on Monday, November 27, things at ARROW are
can physical location of gene on any particular chromosome (except near centromearic region) changes over time due to crossing over ...
If you have been reading my updates over at our website, you will know that the nausea persisted after the infusion of the stem cells, so much so, that he became unable to eat and is on IV Nutrition. He lost his hair and is extremely fatigued. He had another high temperature and rigors on Day +8, so they took out his Hickman Line and tested it for the bacteria that had been previously cultured from his blood. It turned out the tip of the catheter was the source of the infection. This is not uncommon. Once the bacteria makes its way into the bloodstream (unwittingly with an injection through the line or directly crossing over from the chemo and radiation damaged gut), it migrates to the tip of the catheter, replicates and creates a little colony ...
Being on prednisone is a lot like crossing over into the Twilight Zone. Navigating it and figuring out who you are after leaving is hard.
In 2012 Wesleyan alumni, led by director Benh Zeitlen, came together to make the film Beasts of the Southern Wild. Upon the films release it quickly turned into an arthouse success story, crossing over to a wider audience and receiving widespread acclaim. It was nominated for, and won, many awards, including four Independent Spirit Awards, three Gotham Independent Film Awards, and four Oscars.. ...
by monday the 17th, I begin my 7-day uninterrupted mandatory leave (a ruling for all bankers). but given that Im crossing over 3 weekends and 2 official holy-days, my vacation will total to almost half a month. sarap. waste not, because the incoming and forthweek will be busy for me and dear since we are again moving houses. although the move is…
How to Theme Your Animal Crossing Wild World Town. Creating a themed town on Animal Crossing: Wild World is trickier than it looks. It can involve things such as making more players, so the designs of the town can be used more often....
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GP crossover. This figure shows a crossover eventin GP between two binary expression trees. Here, the left sub-treeof parent 1 is swapped with the left sub-tree
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That railroad line is gonna be a real blessing, Grandma announced, rasping her work-roughened hands over the silky material of the crazy-quilt she was making.
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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
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 ...
Gene redundancy is the existence of multiple genes in the genome of an organism that perform the same function. This is the case for many sets of paralogous genes. When an individual gene in such a set is disrupted by mutation or targeted knockout, there can be little effect on phenotype as a result of gene redundancy, whereas the effect is large for the knockout of a gene with only one copy. Gene redundancy most often results from Gene duplication. When a gene is duplicated within a genome, the two copies are initially functionally redundant. Three of the more common mechanisms of gene duplication are retroposition, unequal crossing over, and non-homologous segmental duplication. Retroposition is when the mRNA transcript of a gene is reverse transcribed back into DNA and inserted into the genome at a different location. During unequal crossing over, homologous chromosomes exchange uneven portions of their DNA. This can lead to the transfer of one chromosomes gene to the other chromosome, ...
Lieberman, R and Potter, M, "Crossing over between genes in the immunoglobulin heavy chain linkage group of the mouse." (1969). Subject Strain Bibliography 1969. 635 ...
TY - JOUR. T1 - Blood donor groups and crossing over (I. T2 - Reply). AU - Starkey, J. M.. AU - MacPherson, J. L.. AU - Bolgiano, D. C.. AU - Simon, E. R.. AU - Zuck, T. F.. AU - Sayers, M. H.. PY - 1990. Y1 - 1990. UR - http://www.scopus.com/inward/record.url?scp=0025352526&partnerID=8YFLogxK. UR - http://www.scopus.com/inward/citedby.url?scp=0025352526&partnerID=8YFLogxK. M3 - Article. AN - SCOPUS:0025352526. VL - 263. SP - 3149. JO - JAMA - Journal of the American Medical Association. JF - JAMA - Journal of the American Medical Association. SN - 0098-7484. IS - 23. ER - ...
Gene conversion is an outcome of recombination, causing non-reciprocal transfer of a DNA fragment. Several decades later than the discovery of crossing over, gene conversion was first recognized in fungi when non-Mendelian allelic distortion was observed. Gene conversion occurs when a double-strand break is repaired by using homologous sequences in the genome. In meiosis, there is a strong preference to use the orthologous region (allelic gene conversion), which causes non-Mendelian allelic distortion, but paralogous or duplicated regions can also be used for the repair (inter-locus gene conversion, also referred to as non-allelic and ectopic gene conversion). The focus of this special issue is the latter, interlocus gene conversion; the rate is lower than allelic gene conversion but it has more impact on phenotype because more drastic changes in DNA sequence are involved. [...]
Analysis of genomes shows that many gene copies are found lying next to each other, linked head to tail in an arrangement called a "tandem repeat." This may occur because of errors of the normal recombination machinery that is responsible for DNA repair and crossing over during meiosis. Tandem repeats are susceptible to amplification, which is the further increase in the number of copies. This can occur during crossing over. Normal crossing over pairs up identical segments on homologous chromosomes, and then exchanges them. If the chromosomes each have a tandem repeat, the crossover machinery may line up incorrectly, leaving one homologue with three gene copies and one with only one. Repeating this process over ensuing generations can lead to dozens of extra gene copies.. Duplication of much larger portions of a genome is also possible, including whole chromosomes (called chromosomal aberrations) and even the entire genome (called polyploidy). In each case, the number of copies of a gene ...
The Frequency and Clinical Significance of Sister Chromatid Exchange in the Lymphocyte of Gastric Cancer Patient Exposed to Hypoxia
(KudoZ) English to German translation of sister chromatid exchange: Schwesterchromatid-Austausch [alprostadil product characteristics - Medical: Pharmaceuticals (Medical)].
InferRho is a MCMC based program for jointly estimating the crossing-over and gene-conversion parameters from population genomic datasets under a Bayesian framework. It uses a full-likelihood method to infer the posterior distribution of recombination rates along the sequence under a variable recombination rate model assuming that the ratio of gene- conversion to crossing-over rate ( f ) is uniform along the sequence. The program assumes a prior distribution for background recombination rates and hotspots. The starts, ends and intensities of hotspots are also output by the program in the posterior distribution generated by the MCMC chain. ...
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InferRho is a MCMC based program for jointly estimating the crossing-over and gene-conversion parameters from population genomic datasets under a Bayesian framework. It uses a full-likelihood method to infer the posterior distribution of recombination rates along the sequence under a variable recombination rate model assuming that the ratio of gene- conversion to crossing-over rate ( f ) is uniform along the sequence. The program assumes a prior distribution for background recombination rates and hotspots. The starts, ends and intensities of hotspots are also output by the program in the posterior distribution generated by the MCMC chain. ...
Suppose the "cee" location is under selection for heterozygosity. What this means is that animals that have both the "C" and "c" alleles will leave more progeny in the next generation than animals that are "CC" or "cc" (i.e. homozygous). In the absence of crossing over, however - and remember, crossing over in any given location is an infrequent event - selection for a "Cc" animal will at the same time select for animals that are heterozygous at the other three nearby locations. In this way, these other locations are also selected for heterozygosity, even though the real selection is acting only at the "cee" location. The other locations are merely "hitchhiking" because they are physically connected to the alleles under selection. In a small population over a short timeframe (tens of generations) this effect can be quite pronounced. All it takes is a few locations in the genome to be under selection for heterozygosity, and large swaths of the genome will hitchhike along. This means that a large ...
Lets Talk About It is a free, library-based reading and discussion program for people who want to talk with others about what they have read, presented in collaboration with the Maine State Library.
Homologous recombination is the exchange of pieces of DNA during the formation of eggs and sperm. Recombination allows the chromosomes to shuffle their genetic material, increasing the potential of genetic diversity. Homologous recombination is also known as crossing over. ...
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1. What is the state of the DNA at the end of meiosis I? What about at the end of meiosis II? 2. Why are chromosomes important? 3. How are Meiosis I and Meiosis II different? 4. Name two ways meiosis contributes to genetic recombination. 5. Why do you use non-sister chromatids to demonstrate crossing over? 6. Why is it nec ...
HOTSPOTTER 1.2.1 :: DESCRIPTION HOTSPOTTER is a software for identifying recombination hotspots from population SNP data. ::DEVELOPER Matthew Stephens Lab :: SCREENSHOTS N/A :: REQUIREMENTS Linux /
Crossovers are king, but does that necessarily mean that they are the best vehicle to cart around your family? No. That title is still ...
Well done. The example was a good way of showing how the DNA changes between each phase and the finals sex cells are haploid. Crossing over is an important step and could have been spoken on slightly more. Great video.. ...
In the orginal instructions, she uses two sizes of tubing - one that goes directly on the dowel, othe other, a larger size that slips over the first tubing. It is the largest tubing that gets the genes. This allows you to demonstrate things such as crossing over, etc. I skipped the larger tubing, because my classes dont go into that kind of detail. As a result, I could have skipped the tubing altogether and just painted the stripes on the dowels, but I didnt consider that at the time ...
WOH! Do not fear Crossing over into your promised Land? What is there to fear for me? I was afraid because I still do not know what my promised land looks like, what it is that God has for me, I was afraid of the unknown. I was afraid that I would not hear God and that I would be being still, waiting for a long time. I was afraid that I would not hear God and that I would step out without hearing Him, because I wanted to DO. I was afraid of what people might think, both if I waited much longer and when I cross over into the promised land. I was afraid, and this is one that just echoes Beth Moore from the week 5 video... I was afraid that I WOULD FAIL GOD, that I would not be ENOUGH ...
Page 2 of 3 - Talking with spirits/the unseen - where to even start? - posted in Discussion of Articles & Topics: I have only ever worked with guardians, and guides or spirits within a closed system. I cant work with spirits of the deceased, except for the crossing over process. Once they are processed then they are off limits to me. From what I hear, the ancestor way sounds pretty safe.
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Smith hands his original to the German colonel, who is enraged to find it is blank. It turns out its Smith whos really a triple agent, and the NCOs are who they say they are, double agents. Smith has spent the last two years feeding false information to his German counterpart to set up the identity of a double agent. Really, hes been working for the Brits all along. Schaffer is allowed to retrieve his gun again. Smith announces that the entire operation, including planting the false general and infiltrating the base, was a scam to allow them to expose the German double agents in the U.K. and obtain the names of their collaborators ...
Genetic recombination, the process by which sexually reproducing organisms shuffle their genetic material when producing germ cells, leads to offspring with a new genetic make-up and influences the course of evolution.
The identities of two who men who were killed Sunday night when a CSX train struck their SUV at a Lakeland rail crossing have not been confirmed.
Hi, We have Collection manager 3.7.1 with 2* SCE8000. While both of the SCE8K boxes are sending RDR to single collction manager, i am observing RDR drops from both the SCEs (one is dropping more than other). While checking the same on collection
Its easy to divide a sine wave (curve) into any number of slices so that area of all slices become equal. Its a problem of definite integral. Area...
M25公路通車之初幾乎全程都是雙向6車道,如今過半路段均已拓寬為8车道、12號交流道至14號交流道間拓寬為10车道、14至15號交流道間則已拓寬為雙向12车道。未來更多路段將配合高速公路管控系統(英语:Managed motorways in the United Kingdom)(Managed Motorway System)計畫的擴大實施而跟著拓寬[5]。. 在M25公路東環跨越泰晤士河的路段,分處肯特郡達特福德(南岸)、埃塞克斯郡瑟羅克(北岸)的M25公路起端及終端之間隔水相望,兩者由一般道路--A282公路相连,以方便M25高速公路以外的一般道路車輛也能由此過河。A282公路由一組雙管、各2车道的隧道(英语:Dartford Crossing)及4车道的伊莉莎白二世橋構成,亦被稱為「分層式過河」(Canterbury ...
SUMMARY: Inhabitants of the Hohhot Region in Inner Mongolia who drink high-fluoride (4-15 mg/L) water were compared for their micronucleus (MN) rate and sister chromatid exchange (SCE) frequency in their peripheral blood lymphocytes. In persons with fluorosis as well as those considered "healthy", the MN rafe and SCE frequency were significantly higher (t test) than in a neighbouring control group drinking low-fluorlde water.. Key words: Endemic fluorosis; Inner Mongolia, Hohhot region; Micronucleus (MN) rate; Sister chromatid exchange (SCE) frequency.. Introduction Although widespread in occurrence, fluorine (as fluoride ion, F-) does not have any known physiological requirement. It is generally accepted, however, that long term over-intake of fluoride may cause skeletal as well as dental fluorosis. Many studies on other toxic effects of fluoride have been made, including whether it alters human genetic material and ultimately leads to more serious harm. (1) At present, various test systems 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 ...
Mechanism and Control of Meiotic Recombination. We study homologous recombination and chromosome structural changes that occur during meiosis, using budding yeast as a model system. Recombination, and in particular the crossover products of recombination, are essential for proper chromosome segregation during meiosis. Chromosome mis-segregation caused by defects in meiotic recombination leads to chromosome imbalance in gametes, and these chromosome imbalances are a leading cause of infertility and birth defects in modern human populations. We aim to describe the molecular steps of meiotic recombination, and how they are regulated in parallel with changes in chromosome structure and with cell cycle transitions that occur during meiosis. Because meiosis is an excellent model system to study homologous recombination, our findings also have provided insight into mechanisms by which DNA damage is repaired and genome integrity is maintained during the mitotic cell cycle.. Meiotic recombination ...
Meiosis produces four haploid gametes and is essential for eukaryotic sexual reproduction. One of the critical events during meiotic prophase I is meiotic recombination, which contributes to crossover (CO) formation, thereby ensuring the proper segregation of homologous chromosomes and increasing genetic variation among progeny (Mercier et al., 2015; Lambing et al., 2017; Wang and Copenhaver, 2018). Meiotic recombination is initiated by DNA double strand breaks (DSBs) generated by the topoisomerase-like SPORULATION11 (SPO11), as described in the double strand break repair (DSBR) model (Bergerat et al., 1997; Villeneuve and Hillers, 2001). Repair of DSBs leads to the formation of COs or noncrossovers (Allers and Lichten, 2001; Börner et al., 2004). Many organisms possess two types of COs: interference-sensitive COs (type I), which are dependent on the ZMM proteins (ZIP4, MSH4, MSH5, MER3, HEI10, etc.; Higgins et al., 2004); and interference-insensitive COs (type II), which depend on other ...
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To investigate the relationship between meiotic crossover hot spots and block-like linkage disequilibrium (LD), we have extended our high-resolution studies of the human MHC class II region to a 90-kb segment upstream of the HLA-DOA gene. LD blocks in this region are not as well defined as in the neighboring 210-kb DNA segment but do show two regions of LD breakdown in which coalescent analysis indicates substantial historical recombination. Sperm crossover analysis of one region revealed a novel localized hot spot similar in intensity and morphology to most other MHC hot spots. Crossovers at this hot spot are not obviously affected by a large insertion/deletion polymorphism near the hot spot. The second region of LD breakdown, within the DPB1 gene, shows an extremely low level of sperm crossover activity and does not contain a sperm crossover hot spot. These results highlight the complexity of LD patterns and the importance of experimentally verifying crossover hot spots ...
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 ...
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.. ...
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 ...
The synaptonemal complex (SC) is a widely conserved structure that mediates the intimate alignment of homologous chromosomes during meiotic prophase and is necessary for proper homolog segregation at meiosis I. immediate proof for SUMOs function in SC set up. A meiotic reduction-of-function stress displays decreased sporulation, abnormal degrees of crossover recombination, and reduced SC assembly. […]. ...
PubMed comprises more than 30 million citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.
Critical biological processes such as energy generation and signal transduction are driven by the flow of electrons and ions across the membranes of living cells. As a result, there is substantial interest in creating nanostructured materials that control transport of these charged species across biomembranes. The recent advances in the synthesis of de novo and protein nanostructures for transmembrane ion and electron transport and the mechanistic understanding underlying this transport are described. Moreover, this body of work highlights the promise such nanostructures hold for directing transmembrane transport of charged species as well as challenges that must be overcome to realize that potential. ...
Typically microarrays provide ever more information per experiment. In the drug discovery arena, researchers use microarrays to perform large-scale studies in larger populations than ever before, providing a more comprehensive view of the human genetic variations that cause common diseases ...
Meiosis 1: Homologous chromosomes pair up and their chromatids wrap around each other. Equivalent portions of the chromatids can be exchanged in crossing over. By the end the homologous pairs have separated with one chromosome from each pair going into one of two daughter ...
To investigate the usefulness of sister chromatid exchange (SCE) analysis in lymphocytes as an indicator for mutagenic effects after in vivo exposure to hexavalent chromium (Cr), SCE frequency was analysed in lymphocytes of 44 Cr platers occupationally exposed to hexavalent Cr and 47 controls. Although urinary Cr analysis confirmed that the Cr platers were exposed to Cr, no effects of the exposure on SCE frequency were found. Smokers, both Cr platers and controls, had a significantly higher SCE frequency than non-smokers. These results suggest that SCE analysis in human lymphocytes is not a good indicator of possible mutagenic effects of exposure to hexavalent Cr.. ...
La Plata, Argentina. ABSTRACT The effect of co-culturing varying concentrations of pig and human red blood cells (RBCs) on the baseline frequency of sister chromatid exchanges (SCEs) and cell-cycle progression in pig plasma (PLCs) and whole blood leukocyte cultures (WBCs) was studied. No variation in SCE frequency was observed between pig control WBC and PLC. Addition of pig and human RBCs to pig PLCs did not modify the baseline frequency of SCEs. On the other hand, cell proliferation was slower in PLCs than in WBCs. The addition of pig or human RBCs to PLCs accelerated the cell-cycle progression of pig lymphocytes. When RBCs were added to PLCs the concentration and time sequence of RBC incorporation affected the cell-cycle progression of swine lymphocytes. When doses of pig or human RBCs equivalent to those present in WBCs were added immediately after PLC stimulation, the cell-cycle kinetics were similar to those of WBCs. Shorter co-incubation periods or a reduction in the dose of RBCs made ...
We describe a process in meiotic cells of budding yeast in which chromosomes become joined together in pairs at their centromeres independent of chromosomal homology. These centromeric interactions depend on the synaptonemal complex component Zip1. During meiosis in wild-type diploids, centromere couples are initially nonhomologous and then undergo switching until all couples involve homologs. This transition to homologous coupling depends on Spo11, a protein required for the initiation of meiotic recombination. Regions of synaptonemal complex assembled early in meiosis are often centromere-associated. We propose that centromere coupling facilitates homolog pairing and promotes synapsis initiation. ...
The fine structure of bivalents from golden hamster and house cricket spermatocytes has been studied with a whole mount surface-spreading method combined with negative staining. The elements of the synaptonemal complex show detail of structure which is absent in other preparative procedures. The transverse filaments found in the central region of the synaptonemal complex from both species are straight and have a similar width, 1 6-1 8 nm These filaments occur mainly in bundles The central element differs in architecture in the two species In hamster bivalents it is formed of longitudinal stretches of filaments 1.6-1 8 nm wide and a small amount of an amorphous material similar to that of the lateral elements In the cricket, the central element contains transverse fibrils which are continuous with the transverse filaments of the central region, and an amorphous material lying mainly along the sides of the central element All of the components of the central region of the synaptonemal complex are ...
Central Epidural Steroid Injections (ESI) and Selective Nerve Root Blocks (SNRB) are often used for the non-surgical treatment of lumbar disc herniations and lumbar radiculitis (radiating pain). Numerous authors have reported on their value in treating patients with radicular pain with the possibility of delaying or even obviating the need for surgery in well-selected patients.. There are two well-performed clinical studies in the peer-reviewed medical literature that specifically examined the crossover rates to surgery for patients who received either ESI or SNRB. In a prospective study, Buttermann et al. found a crossover rate to surgery for patients with symptomatic disc herniations treated with ESI of 54% (27/50) . In a separate prospective study, Riew et al. followed patients after selective nerve root blocks and found that similarly 53% (29/55) of their patients had avoided surgery after a selective nerve root block during their initial follow-up of 13-28 months. In a later study that ...
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

Inbred corn plant RQAB7 and seeds thereofInbred corn plant RQAB7 and seeds thereof

This invention further relates to the inbred and hybrid genetic complements of the inbred corn plant RQAB7, and also to the ... This invention further relates to corn seeds and plants produced by crossing the inbred plant RQAB7 with another corn plant, ... and to methods for producing a corn plant produced by crossing the inbred plant RQAB7 with itself or with another corn plant, ... RFLP and genetic isozyme typing profiles of inbred corn plant RQAB7.. Inventors: Larkins; James R. (Waldo, OH) Assignee: Dekalb ...
more infohttp://www.expiredip.com/Search/OpenData.aspx?pn=6,169,231&t=p

crossing over genetic Protocols and Video...'crossing over genetic' Protocols and Video...

Crossing Over, Genetic: The reciprocal exchange of segments at corresponding positions along pairs of homologous Chromosomes by ... Crossing-over typically occurs during Meiosis but it may also occur in the absence of meiosis, for example, with bacterial ...
more infohttps://www.jove.com/keyword/crossing+over+genetic

Genetic Crossing-over Is No Help to Evolution | The Institute for Creation ResearchGenetic 'Crossing-over' Is No Help to Evolution | The Institute for Creation Research

In crossing over, a piece of one chromosome is traded for a piece on an adjacent chromosome. This effectively shuffles genetic ... However, new details of a common cellular genetic shuffling process called "crossing over" reveal a tightly controlled system ... 3 Shuffling of already existing genetic information through crossing over does not provide new information. And if selection ... Shuffling genetic information has long been framed as a biological mechanism that can generate variety as well as fuel ...
more infohttps://www.icr.org/article/4996/373/

How Does Crossing Over Create Genetic Variation? | Reference.comHow Does Crossing Over Create Genetic Variation? | Reference.com

Crossing over creates genetic variation by exchanging DNA between two nonsister chromatids to produce genetically unique ... Crossing over creates genetic variation by exchanging DNA between two nonsister chromatids to produce genetically unique ... The two ways wherein meiosis increases genetic diversity in a species are crossing over and independent assortment of ... Crossing over takes place during meiosis I when two nonsister chromatids exchange DNA material. Approximately two or three ...
more infohttps://www.reference.com/world-view/crossing-over-create-genetic-variation-95505f7acf2d3983

ICM, Genetic Crossings | Ben Turners BlogICM, Genetic Crossings | Ben Turner's Blog

So my code this week is for genetic crossings in Galapag.us. Genetic crossings, Punnett squares, remember those from high ... ICM, Genetic Crossings. Posted on October 13, 2011. by Xeus For this weeks intro to computational media assignment, we were to ...
more infohttp://blog.benturner.com/2011/10/13/icm-genetic-crossings/

Dienekes Anthropology Blog: Fine-scaled human genetic structure (Xing et al. 2009)Dienekes' Anthropology Blog: Fine-scaled human genetic structure (Xing et al. 2009)

Fine-scaled human genetic structure revealed by SNP microarrays. Jinchuan Xing et al.. We report an analysis of more than ... Human genetic variation: the first 50 dimensions. Human genetic variation: 124+ clusters with the Galore approach. How Y-STR ... genetic and self-classifications conflict for some individuals. The 250K data permitted high-level resolution of genetic ... Europeans have a genetic distance of at most some 0,0070 FST from corner to corner. These results are just ridiculous. God damn ...
more infohttp://dienekes.blogspot.com/2009/04/fine-scaled-human-genetic-structure.html?showComment=1241540760000

Dienekes Anthropology Blog: Fine-scaled human genetic structure (Xing et al. 2009)Dienekes' Anthropology Blog: Fine-scaled human genetic structure (Xing et al. 2009)

Fine-scaled human genetic structure revealed by SNP microarrays. Jinchuan Xing et al.. We report an analysis of more than ... Human genetic variation: the first 50 dimensions. Human genetic variation: 124+ clusters with the Galore approach. How Y-STR ... genetic and self-classifications conflict for some individuals. The 250K data permitted high-level resolution of genetic ... Europeans have a genetic distance of at most some 0,0070 FST from corner to corner. These results are just ridiculous. God damn ...
more infohttp://dienekes.blogspot.com/2009/04/fine-scaled-human-genetic-structure.html?showComment=1241480400000

Meiosis and crossing over. Genetic Crossing Over: Definition & Concept. 2019-01-30Meiosis and crossing over. Genetic Crossing Over: Definition & Concept. 2019-01-30

Meiosis and crossing over.The broken sections are then exchanged between the chromosomes to form complete new units, and each ... The Genetic Code: Influence of Mitosis, Meiosis & Crossing Over. Mitotic crossing over take place when homologous chromosomal ... I know I just got to prophase I. A double crossing over Chromosomal crossover or crossing over is the exchange of genetic ... Meiosis and crossing over. What is crossing over and when does it occur? 2019-01-30. Meiosis and crossing over Rating: 8,6/10 ...
more infohttp://fetranspordocs.com.br/meiosis-and-crossing-over.html

Crossing Wild and Conventional Wheat Boosts Protein, Avoids Genetic Modification - Scientific AmericanCrossing Wild and Conventional Wheat Boosts Protein, Avoids Genetic Modification - Scientific American

"The exact effect depends on the genetic background of the [wheat] variety and the environment where the gene is used," ...
more infohttps://www.scientificamerican.com/article/crossing-wild-and-convent/

English VersionEnglish Version

Strawberry Cookiezs genetic history and all cannabis hybrids and crossings who have Epik Genetics Strawberry Cookiez into his ... Strawberry Cookiez Hybrids / Crossings. Hybrids / Crossings (min. 1. Generation):. *Strawberry N Mango » Strawberry Cookiez x ... All crossings of Strawberry Cookiez can be visualized easily with our unique dynamic hybrid map! Click and zoom into our map to ... Lineages :: Crossings & Hybrids. Map all Strawberry Cookiez parents. All parents of Strawberry Cookiez can be visualized easily ...
more infohttp://en.seedfinder.eu/strain-info/Strawberry_Cookiez/Epik_Genetics/genealogy/

Crossing Over - Crossing Over As A Genetic Tool - Chromosome, Differences, Interference, and Loci
	  	   - JRank Articles
	  	Crossing Over - Crossing Over As A Genetic Tool - Chromosome, Differences, Interference, and Loci - JRank Articles

Mechanics Of Crossing Over, The Consequences Of Crossing Over, X-y Crossovers And Unequal Crossovers ... back] Crossing Over - X-y Crossovers And Unequal Crossovers Citing this material. Please include a link to this page if you ... Multiple comparisons of crossing over among multiple loci allows these loci to be mapped, or placed in relative position to one ... Loci that are on the same chromosome are all physically linked to one another, but they can be separated by crossing over. ...
more infohttp://medicine.jrank.org/pages/2108/Crossing-Over-Crossing-Over-Genetic-Tool.html

English VersionEnglish Version

Mango Puffs genetic history and all cannabis hybrids and crossings who have Gage Green Genetics Mango Puff into his geneology ... Mango Puff Hybrids / Crossings. Hybrids / Crossings (min. 1. Generation):. *Blue Mangos » Blue Dream x Mango Puff F1 ... Lineages :: Crossings & Hybrids. Map all Mango Puff parents. All parents of Mango Puff can be visualized easily with our unique ... All crossings of Mango Puff can be visualized easily with our unique dynamic hybrid map! Click and zoom into our map to find ...
more infohttp://en.seedfinder.eu/strain-info/Mango_Puff/Gage_Green_Genetics/genealogy/

Public participation in genetic databases: crossing the boundaries between biobanks and forensic DNA databases through the...Public participation in genetic databases: crossing the boundaries between biobanks and forensic DNA databases through the...

Public participation in genetic databases: crossing the boundaries between biobanks and forensic DNA databases through the ... As a reflection of this, public participation, or the involvement of citizens in genetic databases, has been approached ...
more infohttps://phgkb.cdc.gov/PHGKB/phgHome.action?action=forward&dbsource=phg&id=7838

The Variant Explorer: a cloud-based data integration and visualization system for improving clinical interpretation of...The Variant Explorer: a cloud-based data integration and visualization system for improving clinical interpretation of...

... of this proposal is to dramatically improve speed and accuracy in clinical decision-making for patients requiring a genetic ... and efficiency in genetic variant analysis so that patients suffering from genetic diseases suitable for NGS-based analyses ... See 7 grants from Xing Xu See grants from Solve, Inc. *Abstract ... in analyzing how sequenced genetic variants cause genetic ... The single most intractable challenge is that current practices for the analysis of sequenced genetic variants require an ...
more infohttp://grantome.com/grant/NIH/R43-GM117644-01

Investigation of RNA Binding Protein Pumilio as a Genetic Modifier of  by Xing Du"Investigation of RNA Binding Protein Pumilio as a Genetic Modifier of " by Xing Du

Genetic screens designed to identify genes interacting with mutant CHMP2B represents a key approach in solving the puzzle. ... Genetic screens designed to identify genes interacting with mutant CHMP2B represents a key approach in solving the puzzle. ... Du, X. Investigation of RNA Binding Protein Pumilio as a Genetic Modifier of Mutant CHMP2B in Frontotemporal Dementia (FTD): A ... Investigation of RNA Binding Protein Pumilio as a Genetic Modifier of Mutant CHMP2B in Frontotemporal Dementia (FTD): A Masters ...
more infohttps://escholarship.umassmed.edu/gsbs_diss/846/

Volume 11, Issue 2 | The American Journal of Tropical Medicine and HygieneVolume 11, Issue 2 | The American Journal of Tropical Medicine and Hygiene

Genetic Crossing of Pigmented Caribbean Strains with an Albino Venezuelan Strain of Australorbis Glabratus Charles S. Richards ...
more infohttp://www.ajtmh.org/content/journals/14761645/11/2

Search Results - AccessScience from McGraw-Hill EducationSearch Results - AccessScience from McGraw-Hill Education

Crossing-over (genetics) 5 results. Did you mean: crossing-over (genetic)? Definition ... Crossing-over (genetics). The process whereby one or more gene alleles present in one chromosome may be exchanged with their ... The formation of a new plant that is either an exact copy or recombination of the genetic makeup of its parents. There are ...
more infohttps://www.accessscience.com/search?topics=Botany&start=0&q=Crossing-over+%28genetics%29&mode=AND&rows=10

whales | Southern Fried Sciencewhales | Southern Fried Science

Fish crossing genetic borders as oceans warm. By Matthew Berger, for OceansDeeply. ...
more infohttp://www.southernfriedscience.com/tag/whales/

Genetics - Page 58 - Biology Forum | Biology-Online Dictionary, Blog & ForumGenetics - Page 58 - Biology Forum | Biology-Online Dictionary, Blog & Forum

genetic crossing why isnt it 1/4 :( Last post by d00d « Tue Apr 25, 2006 9:05 pm ... Genetic Crossing Last post by MrMistery « Mon Apr 24, 2006 6:03 pm ... Crossing over.. Last post by sdekivit « Sun May 07, 2006 9:01 am ... Genetic maps Last post by LilKim « Mon May 15, 2006 10:05 pm ... Genetic mapping Last post by hurly « Sat May 13, 2006 4:53 am ...
more infohttps://www.biology-online.org/biology-forum/viewforum.php?f=17&start=1425

14.   Crossing-over involves the exchange of genetic information between 
 
     A. homologues. 
B. sex chromosomes. 
C. sister...14. Crossing-over involves the exchange of genetic information between A. homologues. B. sex chromosomes. C. sister...

Crossing-over involves the exchange of genetic information between A. homologues. B. sex chromosomes. C. sister chromatids. D. ... Crossing-over involves the exchange of genetic information between A. homologues. B. sex chromosomes. C. sister chromatids. D. ... Crossing-over involves the exchange of genetic information between A. homologues. B. sex chromosomes. C. sister chromatids. D. ... Which of the following processes occurs during meiosis and not mitosis? A. Crossing-over B. Cytokinesis C. Crossing-under D. ...
more infohttps://www.weegy.com/?ConversationId=FOB6OTGQ

The Model Legume Medicago truncatula | Molecular Microbiology | Microbiology & Virology | Life Sciences | Subjects | WileyThe Model Legume Medicago truncatula | Molecular Microbiology | Microbiology & Virology | Life Sciences | Subjects | Wiley

... and the availability of multiple genetic and genomic tools. This reference provides comprehensive coverage of the Model Legume ... 12.10.4. A simple method for genetic crossing in Medicago truncatula. Alexandre Boscari ... A Snapshot of Functional Genetic Studies in Medicago truncatula. Jerome Verdier. 2.2. Medicago truncatula as an ecological, ... genetic engineering strategies. Massimo Confalonieri. 14.2. Agrobacterium-mediated transformation of Medicago truncatula cell ...
more infohttps://www.wiley.com/en-us/The+Model+Legume+Medicago+truncatula-p-9781119409168

The Model Legume Medicago truncatula | Molecular Microbiology | Microbiology & Virology | Life Sciences | Subjects | WileyThe Model Legume Medicago truncatula | Molecular Microbiology | Microbiology & Virology | Life Sciences | Subjects | Wiley

12.10.4. A simple method for genetic crossing in Medicago truncatula. Alexandre Boscari ... A Snapshot of Functional Genetic Studies in Medicago truncatula. Jerome Verdier. 2.2. Medicago truncatula as an ecological, ... genetic engineering strategies. Massimo Confalonieri. 14.2. Agrobacterium-mediated transformation of Medicago truncatula cell ... Genomic and genetic markers in M. truncatula. 12.8.1. Development and characterization of Simple Sequence Repeat (SSR) markers ...
more infohttps://www.wiley.com/en-bi/The+Model+Legume+Medicago+truncatula-p-9781119409168

Long-Range Repression by Multiple Polycomb Group (PcG) Proteins Targeted by Fusion to a Defined DNA-Binding Domain in...Long-Range Repression by Multiple Polycomb Group (PcG) Proteins Targeted by Fusion to a Defined DNA-Binding Domain in...

Genetic crossing schemes used in ZnF-PcG studies. (A) Crosses used to study the effect of tethered ZnF-PcG fusion proteins on ... Effect of the ph409 mutation on the eye-color phenotype of four classes of su(Hw)-, SUPor P male progeny generated by crossing ... Genetic crosses involved in the ph409 test are outlined in Figure 3B. Females were constructed that were su(Hw)- and ... Genetic tests showed that reduction in PH dosage relieved tether-based repression by PC and SCM at this site (Figures 3 and 7 ...
more infohttps://www.genetics.org/content/158/1/291?ijkey=ff0d08aec7e635f812ff10d5ada241a5d77d27ec&keytype2=tf_ipsecsha

Plus itPlus it

FUF1 were generated by genetic crossing. Floral senescence/abscission was delayed to later than position 10 (Fig. 6N, 1) in 35S ... FYF were generated by genetic crossing. In the 35S:FYF Arabidopsis, floral senescence/abscission was delayed until after ... The transactivation line (FUF1:FUF1+SRDX) was obtained by crossing the effector line and the activator line. ...
more infohttp://www.plantphysiol.org/content/168/4/1666

Plus itPlus it

Double mutants were generated by genetic crossing. To generate mutated versions of 35S:HDA15-GFP transgenic lines, the mutated ... 35S:HDA15-GFP was introduced into the hy5-215 allele by crossing (Oyama et al., 1997). The hypocotyls of 4-d-old 35S:HDA15-GFP ... Next, 35S:HY5-GFP was also introduced into the hda15 background by crossing. As reported in Ang et al. (1998), 35S:HY5-GFP ... To test the genetic relationship between HDA15 and the photoreceptors, PHYA and PHYB, 35S:HDA15-GFP was introduced into phyA- ...
more infohttp://www.plantphysiol.org/content/180/3/1450
  • However, new details of a common cellular genetic shuffling process called "crossing over" reveal a tightly controlled system that operates under strict parameters and requires highly specified cellular machinery. (icr.org)
  • New insights into the nature of crossing over reveal that precisely specified proteins called "condensins" are deployed at just the right times and in the right amounts to help regulate crossing over. (icr.org)
  • Sager is known primarily for using classical genetic methods to demonstrate the presence of a hereditary system in the chloroplasts of plants and for establishing Chlamydomonas reinhardtii as a model organism for the study of chloroplasts. (encyclopedia.com)
  • Our results emphasize the correlation of genetic and geographic distances and highlight other elements, including social factors that have contributed to population structure. (blogspot.com)
  • The investigation of interference is important because accurate modeling of interference will provide better estimates of true genetic map length and intermarker distances, and more accurate mapping of trait loci. (jrank.org)
  • anticipation Phenomenon in which the severity of a genetic condition appears to become more severe and/or arise at an earlier age with subsequent generations (seen in many trinucleotide repeat permutations). (kumc.edu)
  • 3 Shuffling of already existing genetic information through crossing over does not provide new information. (icr.org)
  • This research will provide solutions for faster and more accurate genetic diagnoses and ultimately support the development of precision medicine. (grantome.com)
  • Genetic screens designed to identify genes interacting with mutant CHMP2B represents a key approach in solving the puzzle. (umassmed.edu)
  • If crossing over actually helped largescale evolution, then more than a mere re-shuffle of pre-existing information , according to a tightly regulated system, would be observed. (icr.org)
  • The Variant Explorer: a cloud-based data integration and visualization system for improving clinical interpretation of sequenced genetic variants. (grantome.com)
  • The proposed product, SolveBio's Variant Explorer (VE), is a cloud- based graphical software system that assists in variant interpretation, or the ascertaining of the clinical significance of sequenced genetic variant. (grantome.com)
  • In this Phase I SBIR, SolveBio plans to develop a cloud-based software system that combines disparate and complex reference databases to improve efficiency and accuracy in analyzing how sequenced genetic variants cause genetic diseases. (grantome.com)
  • Multiple comparisons of crossing over among multiple loci allows these loci to be mapped, or placed in relative position to one another. (jrank.org)
  • Plant scientists are drawn to models because of their ease of manipulation, simple genome organization, rapid life cycles, and the availability of multiple genetic and genomic tools. (wiley.com)
  • The author, George Johnson, also illustrated selection: "Thoroughbred racehorses are all descendants of a small initial number of individuals, and selection for speed has accomplished all it can with this limited amount of genetic variability-the winning times in major races ceased to improve decades ago. (icr.org)
  • The exact effect depends on the genetic background of the [wheat] variety and the environment where the gene is used," Dubcovsky notes. (scientificamerican.com)
  • All individuals are accurately classified into continental groups using a model-based clustering algorithm, but between closely related populations, genetic and self-classifications conflict for some individuals. (blogspot.com)