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[PMID]: 28743762 [Au] Autor: Hum YF; Jinks-Robertson S [Ad] Endereço: Department of Molecular Genetics and Microbiology, Duke University, Durham, North Carolina 27710. [Ti] Título: Mitotic Gene Conversion Tracts Associated with Repair of a Defined Double-Strand Break in . [So] Source: Genetics;207(1):115-128, 2017 09. [Is] ISSN: 1943-2631 [Cp] País de publicação: United States [La] Idioma: eng [Ab] Resumo: Mitotic recombination between homologous chromosomes leads to the uncovering of recessive alleles through loss of heterozygosity. In the current study, a defined double-strand break was used to initiate reciprocal loss of heterozygosity between diverged homologs of chromosome IV in These events resulted from the repair of two broken chromatids, one of which was repaired as a crossover and the other as a noncrossover. Associated gene conversion tracts resulting from the donor-directed repair of mismatches formed during strand exchange (heteroduplex DNA) were mapped using microarrays. Gene conversion tracts associated with individual crossover and noncrossover events were similar in size and position, with half of the tracts being unidirectional and mapping to only one side of the initiating break. Among crossover events, this likely reflected gene conversion on only one side of the break, with restoration-type repair occurring on the other side. For noncrossover events, an ectopic system was used to directly compare gene conversion tracts produced in a wild-type strain to heteroduplex DNA tracts generated in the absence of the Mlh1 mismatch-repair protein. There was a strong bias for unidirectional tracts in the absence, but not in the presence, of Mlh1 This suggests that mismatch repair acts on heteroduplex DNA that is only transiently present in noncrossover intermediates of the synthesis dependent strand annealing pathway. Although the molecular features of events associated with loss of heterozygosity generally agreed with those predicted by current recombination models, there were unexpected complexities in associated gene conversion tracts. [Mh] Termos MeSH primário: Quebras de DNA de Cadeia Dupla Conversão Gênica Mitose/genética Reparo de DNA por Recombinação Saccharomyces cerevisiae/genética [Mh] Termos MeSH secundário: Troca Genética Saccharomyces cerevisiae/citologia [Pt] Tipo de publicação: JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T; RESEARCH SUPPORT, N.I.H., EXTRAMURAL [Em] Mês de entrada: 1712 [Cu] Atualização por classe: 180309 [Lr] Data última revisão: 180309 [Sb] Subgrupo de revista: IM [Da] Data de entrada para processamento: 170727 [St] Status: MEDLINE [do] DOI: 10.1534/genetics.117.300057

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[PMID]: 29258113 [Au] Autor: Silipigni R; Monfrini E; Baccarin M; Giangiobbe S; Lalatta F; Guerneri S; Bedeschi MF [Ad] Endereço: Laboratory of Medical Genetics, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy. [Ti] Título: Familial Duplication/Deletion of 1q42.13q43 as Meiotic Consequence of an Intrachromosomal Insertion in Chromosome 1. [So] Source: Cytogenet Genome Res;153(2):73-80, 2017. [Is] ISSN: 1424-859X [Cp] País de publicação: Switzerland [La] Idioma: eng [Ab] Resumo: Rearrangements of the region 1q42.13q43 are rare, with only 7 cases reported to date. The imbalances described are usually the result of inherited translocations with other chromosomes. Moreover, few cases of both inter- and intrachromosomal deletions/duplications detected cytogenetically have been described. We report the molecular cytogenetic characterization of an inverted insertion involving the region 1q42.13q43 and segregating in 2 generations of a family. The deletion and the duplication of the same segment were detected in 2 affected family members. SNP array analysis showed the familial origin of the deletion/duplication due to the occurrence of a crossing-over during meiosis. Our report underlines the importance of determining the correct origin of chromosomal aberrations using different molecular cytogenetic tests in order to provide a good estimation of the reproductive risk for the members of the family. [Mh] Termos MeSH primário: Anormalidades Múltiplas/genética Cromossomos Humanos Par 1/genética Troca Genética Genes Duplicados Meiose Mutagênese Insercional Deleção de Sequência [Mh] Termos MeSH secundário: Adulto Criança Cromossomos Humanos Par 1/ultraestrutura Hibridização Genômica Comparativa Face/anormalidades Feminino Aconselhamento Genético Seres Humanos Recém-Nascido Deficiência Intelectual/genética Masculino Miringoesclerose/genética Linhagem Fenótipo Polimorfismo de Nucleotídeo Único Quadriplegia/genética Adulto Jovem [Pt] Tipo de publicação: CASE REPORTS; JOURNAL ARTICLE [Em] Mês de entrada: 1802 [Cu] Atualização por classe: 180220 [Lr] Data última revisão: 180220 [Sb] Subgrupo de revista: IM [Da] Data de entrada para processamento: 171220 [St] Status: MEDLINE [do] DOI: 10.1159/000485226

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[PMID]: 28827832 [Au] Autor: Al-Sweel N; Raghavan V; Dutta A; Ajith VP; Di Vietro L; Khondakar N; Manhart CM; Surtees JA; Nishant KT; Alani E [Ad] Endereço: Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America. [Ti] Título: mlh3 mutations in baker's yeast alter meiotic recombination outcomes by increasing noncrossover events genome-wide. [So] Source: PLoS Genet;13(8):e1006974, 2017 Aug. [Is] ISSN: 1553-7404 [Cp] País de publicação: United States [La] Idioma: eng [Ab] Resumo: Mlh1-Mlh3 is an endonuclease hypothesized to act in meiosis to resolve double Holliday junctions into crossovers. It also plays a minor role in eukaryotic DNA mismatch repair (MMR). To understand how Mlh1-Mlh3 functions in both meiosis and MMR, we analyzed in baker's yeast 60 new mlh3 alleles. Five alleles specifically disrupted MMR, whereas one (mlh3-32) specifically disrupted meiotic crossing over. Mlh1-mlh3 representatives for each class were purified and characterized. Both Mlh1-mlh3-32 (MMR+, crossover-) and Mlh1-mlh3-45 (MMR-, crossover+) displayed wild-type endonuclease activities in vitro. Msh2-Msh3, an MSH complex that acts with Mlh1-Mlh3 in MMR, stimulated the endonuclease activity of Mlh1-mlh3-32 but not Mlh1-mlh3-45, suggesting that Mlh1-mlh3-45 is defective in MSH interactions. Whole genome recombination maps were constructed for wild-type and MMR+ crossover-, MMR- crossover+, endonuclease defective and null mlh3 mutants in an S288c/YJM789 hybrid background. Compared to wild-type, all of the mlh3 mutants showed increases in the number of noncrossover events, consistent with recombination intermediates being resolved through alternative recombination pathways. Our observations provide a structure-function map for Mlh3 that reveals the importance of protein-protein interactions in regulating Mlh1-Mlh3's enzymatic activity. They also illustrate how defective meiotic components can alter the fate of meiotic recombination intermediates, providing new insights for how meiotic recombination pathways are regulated. [Mh] Termos MeSH primário: Recombinação Homóloga/genética Proteína 1 Homóloga a MutL/genética Proteínas MutL/genética Mapas de Interação de Proteínas/genética Proteínas de Saccharomyces cerevisiae/genética [Mh] Termos MeSH secundário: Alelos Troca Genética Reparo de Erro de Pareamento de DNA/genética Genoma Fúngico Meiose/genética Saccharomyces cerevisiae/genética Relação Estrutura-Atividade [Pt] Tipo de publicação: JOURNAL ARTICLE [Nm] Nome de substância: 0 (MLH1 protein, S cerevisiae); 0 (MLH3 protein, S cerevisiae); 0 (Saccharomyces cerevisiae Proteins); EC 3.6.1.3 (MutL Protein Homolog 1); EC 3.6.1.3 (MutL Proteins) [Em] Mês de entrada: 1709 [Cu] Atualização por classe: 171110 [Lr] Data última revisão: 171110 [Sb] Subgrupo de revista: IM [Da] Data de entrada para processamento: 170823 [St] Status: MEDLINE [do] DOI: 10.1371/journal.pgen.1006974

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[PMID]: 28800596 [Au] Autor: Sun S; Yadav V; Billmyre RB; Cuomo CA; Nowrousian M; Wang L; Souciet JL; Boekhout T; Porcel B; Wincker P; Granek JA; Sanyal K; Heitman J [Ad] Endereço: Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America. [Ti] Título: Fungal genome and mating system transitions facilitated by chromosomal translocations involving intercentromeric recombination. [So] Source: PLoS Biol;15(8):e2002527, 2017 Aug. [Is] ISSN: 1545-7885 [Cp] País de publicação: United States [La] Idioma: eng [Ab] Resumo: Species within the human pathogenic Cryptococcus species complex are major threats to public health, causing approximately 1 million annual infections globally. Cryptococcus amylolentus is the most closely known related species of the pathogenic Cryptococcus species complex, and it is non-pathogenic. Additionally, while pathogenic Cryptococcus species have bipolar mating systems with a single large mating type (MAT) locus that represents a derived state in Basidiomycetes, C. amylolentus has a tetrapolar mating system with 2 MAT loci (P/R and HD) located on different chromosomes. Thus, studying C. amylolentus will shed light on the transition from tetrapolar to bipolar mating systems in the pathogenic Cryptococcus species, as well as its possible link with the origin and evolution of pathogenesis. In this study, we sequenced, assembled, and annotated the genomes of 2 C. amylolentus isolates, CBS6039 and CBS6273, which are sexual and interfertile. Genome comparison between the 2 C. amylolentus isolates identified the boundaries and the complete gene contents of the P/R and HD MAT loci. Bioinformatic and chromatin immunoprecipitation sequencing (ChIP-seq) analyses revealed that, similar to those of the pathogenic Cryptococcus species, C. amylolentus has regional centromeres (CENs) that are enriched with species-specific transposable and repetitive DNA elements. Additionally, we found that while neither the P/R nor the HD locus is physically closely linked to its centromere in C. amylolentus, and the regions between the MAT loci and their respective centromeres show overall synteny between the 2 genomes, both MAT loci exhibit genetic linkage to their respective centromere during meiosis, suggesting the presence of recombinational suppressors and/or epistatic gene interactions in the MAT-CEN intervening regions. Furthermore, genomic comparisons between C. amylolentus and related pathogenic Cryptococcus species provide evidence that multiple chromosomal rearrangements mediated by intercentromeric recombination have occurred during descent of the 2 lineages from their common ancestor. Taken together, our findings support a model in which the evolution of the bipolar mating system was initiated by an ectopic recombination event mediated by similar repetitive centromeric DNA elements shared between chromosomes. This translocation brought the P/R and HD loci onto the same chromosome, and further chromosomal rearrangements then resulted in the 2 MAT loci becoming physically linked and eventually fusing to form the single contiguous MAT locus that is now extant in the pathogenic Cryptococcus species. [Mh] Termos MeSH primário: Cryptococcus/citologia Cryptococcus/genética Genes Fúngicos Tipo Acasalamento Genoma Fúngico Meiose Translocação Genética [Mh] Termos MeSH secundário: Imunoprecipitação da Cromatina Biologia Computacional Troca Genética Cryptococcus/crescimento & desenvolvimento Cryptococcus/fisiologia Cryptococcus neoformans/citologia Cryptococcus neoformans/genética Cryptococcus neoformans/fisiologia Epistasia Genética Evolução Molecular Ligação Genética Loci Gênicos Estruturas Genéticas Desequilíbrio de Ligação Anotação de Sequência Molecular Recombinação Genética Análise de Sequência de RNA Especificidade da Espécie Sintenia [Pt] Tipo de publicação: COMPARATIVE STUDY; JOURNAL ARTICLE [Em] Mês de entrada: 1710 [Cu] Atualização por classe: 171014 [Lr] Data última revisão: 171014 [Sb] Subgrupo de revista: IM [Da] Data de entrada para processamento: 170812 [St] Status: MEDLINE [do] DOI: 10.1371/journal.pbio.2002527

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[PMID]: 28592499 [Au] Autor: Morgan AP; Gatti DM; Najarian ML; Keane TM; Galante RJ; Pack AI; Mott R; Churchill GA; de Villena FP [Ad] Endereço: Department of Genetics, University of North Carolina, Chapel Hill, North Carolina 27599-7264. [Ti] Título: Structural Variation Shapes the Landscape of Recombination in Mouse. [So] Source: Genetics;206(2):603-619, 2017 Jun. [Is] ISSN: 1943-2631 [Cp] País de publicação: United States [La] Idioma: eng [Ab] Resumo: Meiotic recombination is an essential feature of sexual reproduction that ensures faithful segregation of chromosomes and redistributes genetic variants in populations. Multiparent populations such as the Diversity Outbred (DO) mouse stock accumulate large numbers of crossover (CO) events between founder haplotypes, and thus present a unique opportunity to study the role of genetic variation in shaping the recombination landscape. We obtained high-density genotype data from [Formula: see text] DO mice, and localized 2.2 million CO events to intervals with a median size of 28 kb. The resulting sex-averaged genetic map of the DO population is highly concordant with large-scale (order 10 Mb) features of previously reported genetic maps for mouse. To examine fine-scale (order 10 kb) patterns of recombination in the DO, we overlaid putative recombination hotspots onto our CO intervals. We found that CO intervals are enriched in hotspots compared to the genomic background. However, as many as [Formula: see text] of CO intervals do not overlap any putative hotspots, suggesting that our understanding of hotspots is incomplete. We also identified coldspots encompassing 329 Mb, or [Formula: see text] of observable genome, in which there is little or no recombination. In contrast to hotspots, which are a few kilobases in size, and widely scattered throughout the genome, coldspots have a median size of 2.1 Mb and are spatially clustered. Coldspots are strongly associated with copy-number variant (CNV) regions, especially multi-allelic clusters, identified from whole-genome sequencing of 228 DO mice. Genes in these regions have reduced expression, and epigenetic features of closed chromatin in male germ cells, which suggests that CNVs may repress recombination by altering chromatin structure in meiosis. Our findings demonstrate how multiparent populations, by bridging the gap between large-scale and fine-scale genetic mapping, can reveal new features of the recombination landscape. [Mh] Termos MeSH primário: Variações do Número de Cópias de DNA/genética Recombinação Homóloga/genética Meiose/genética Recombinação Genética [Mh] Termos MeSH secundário: Animais Mapeamento Cromossômico Cromossomos/genética Troca Genética Genoma Genótipo Haplótipos Masculino Camundongos [Pt] Tipo de publicação: JOURNAL ARTICLE [Em] Mês de entrada: 1707 [Cu] Atualização por classe: 170714 [Lr] Data última revisão: 170714 [Sb] Subgrupo de revista: IM [Da] Data de entrada para processamento: 170609 [St] Status: MEDLINE [do] DOI: 10.1534/genetics.116.197988

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[PMID]: 28533438 [Au] Autor: Darrier B; Rimbert H; Balfourier F; Pingault L; Josselin AA; Servin B; Navarro J; Choulet F; Paux E; Sourdille P [Ad] Endereço: Genetics, Diversity and Ecophysiology of Cereals, Institut National de la Recherche Agronomique, Université Blaise Pascal, 63000 Clermont-Ferrand, France. [Ti] Título: High-Resolution Mapping of Crossover Events in the Hexaploid Wheat Genome Suggests a Universal Recombination Mechanism. [So] Source: Genetics;206(3):1373-1388, 2017 Jul. [Is] ISSN: 1943-2631 [Cp] País de publicação: United States [La] Idioma: eng [Ab] Resumo: During meiosis, crossovers (COs) create new allele associations by reciprocal exchange of DNA. In bread wheat ( L.), COs are mostly limited to subtelomeric regions of chromosomes, resulting in a substantial loss of breeding efficiency in the proximal regions, though these regions carry ∼60-70% of the genes. Identifying sequence and/or chromosome features affecting recombination occurrence is thus relevant to improve and drive recombination. Using the recent release of a reference sequence of chromosome 3B and of the draft assemblies of the 20 other wheat chromosomes, we performed fine-scale mapping of COs and revealed that 82% of COs located in the distal ends of chromosome 3B representing 19% of the chromosome length. We used 774 SNPs to genotype 180 varieties representative of the Asian and European genetic pools and a segregating population of 1270 F lines. We observed a common location for ancestral COs (predicted through linkage disequilibrium) and the COs derived from the segregating population. We delineated 73 small intervals (<26 kb) on chromosome 3B that contained 252 COs. We observed a significant association of COs with genic features (73 and 54% in recombinant and nonrecombinant intervals, respectively) and with those expressed during meiosis (67% in recombinant intervals and 48% in nonrecombinant intervals). Moreover, while the recombinant intervals contained similar amounts of retrotransposons and DNA transposons (42 and 53%), nonrecombinant intervals had a higher level of retrotransposons (63%) and lower levels of DNA transposons (28%). Consistent with this, we observed a higher frequency of a DNA motif specific to the DNA transposon in recombinant intervals. [Mh] Termos MeSH primário: Cromossomos de Plantas/genética Troca Genética Genoma de Planta Poliploidia Triticum/genética [Mh] Termos MeSH secundário: Mapeamento Cromossômico/métodos Elementos de DNA Transponíveis [Pt] Tipo de publicação: JOURNAL ARTICLE [Nm] Nome de substância: 0 (DNA Transposable Elements) [Em] Mês de entrada: 1710 [Cu] Atualização por classe: 171019 [Lr] Data última revisão: 171019 [Sb] Subgrupo de revista: IM [Da] Data de entrada para processamento: 170524 [St] Status: MEDLINE [do] DOI: 10.1534/genetics.116.196014

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[PMID]: 28505149 [Au] Autor: Claeys Bouuaert C; Keeney S [Ad] Endereço: Molecular Biology Program, Memorial Sloan Kettering Cancer Center and Howard Hughes Medical Institute, New York, New York, United States of America. [Ti] Título: Distinct DNA-binding surfaces in the ATPase and linker domains of MutLγ determine its substrate specificities and exert separable functions in meiotic recombination and mismatch repair. [So] Source: PLoS Genet;13(5):e1006722, 2017 May. [Is] ISSN: 1553-7404 [Cp] País de publicação: United States [La] Idioma: eng [Ab] Resumo: Mlh1-Mlh3 (MutLγ) is a mismatch repair factor with a central role in formation of meiotic crossovers, presumably through resolution of double Holliday junctions. MutLγ has DNA-binding, nuclease, and ATPase activities, but how these relate to one another and to in vivo functions are unclear. Here, we combine biochemical and genetic analyses to characterize Saccharomyces cerevisiae MutLγ. Limited proteolysis and atomic force microscopy showed that purified recombinant MutLγ undergoes ATP-driven conformational changes. In vitro, MutLγ displayed separable DNA-binding activities toward Holliday junctions (HJ) and, surprisingly, single-stranded DNA (ssDNA), which was not predicted from current models. MutLγ bound DNA cooperatively, could bind multiple substrates simultaneously, and formed higher-order complexes. FeBABE hydroxyl radical footprinting indicated that the DNA-binding interfaces of MutLγ for ssDNA and HJ substrates only partially overlap. Most contacts with HJ substrates were located in the linker regions of MutLγ, whereas ssDNA contacts mapped within linker regions as well as the N-terminal ATPase domains. Using yeast genetic assays for mismatch repair and meiotic recombination, we found that mutations within different DNA-binding surfaces exert separable effects in vivo. For example, mutations within the Mlh1 linker conferred little or no meiotic phenotype but led to mismatch repair deficiency. Interestingly, mutations in the N-terminal domain of Mlh1 caused a stronger meiotic defect than mlh1Δ, suggesting that the mutant proteins retain an activity that interferes with alternative recombination pathways. Furthermore, mlh3Δ caused more chromosome missegregation than mlh1Δ, whereas mlh1Δ but not mlh3Δ partially alleviated meiotic defects of msh5Δ mutants. These findings illustrate functional differences between Mlh1 and Mlh3 during meiosis and suggest that their absence impinges on chromosome segregation not only via reduced formation of crossovers. Taken together, our results offer insights into the structure-function relationships of the MutLγ complex and reveal unanticipated genetic relationships between components of the meiotic recombination machinery. [Mh] Termos MeSH primário: Trifosfato de Adenosina/metabolismo Troca Genética Reparo de Erro de Pareamento de DNA Proteína 1 Homóloga a MutL/metabolismo Proteínas MutL/metabolismo Proteínas de Saccharomyces cerevisiae/metabolismo [Mh] Termos MeSH secundário: Animais Segregação de Cromossomos DNA Cruciforme DNA de Cadeia Simples/metabolismo Meiose Proteína 1 Homóloga a MutL/química Proteína 1 Homóloga a MutL/genética Proteínas MutL/química Proteínas MutL/genética Ligação Proteica Domínios Proteicos Saccharomyces cerevisiae/genética Saccharomyces cerevisiae/metabolismo Proteínas de Saccharomyces cerevisiae/química Proteínas de Saccharomyces cerevisiae/genética Células Sf9 Spodoptera Especificidade por Substrato [Pt] Tipo de publicação: JOURNAL ARTICLE [Nm] Nome de substância: 0 (DNA, Cruciform); 0 (DNA, Single-Stranded); 0 (MLH1 protein, S cerevisiae); 0 (MLH3 protein, S cerevisiae); 0 (Saccharomyces cerevisiae Proteins); 8L70Q75FXE (Adenosine Triphosphate); EC 3.6.1.3 (MutL Protein Homolog 1); EC 3.6.1.3 (MutL Proteins) [Em] Mês de entrada: 1706 [Cu] Atualização por classe: 170615 [Lr] Data última revisão: 170615 [Sb] Subgrupo de revista: IM [Da] Data de entrada para processamento: 170516 [St] Status: MEDLINE [do] DOI: 10.1371/journal.pgen.1006722

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[PMID]: 28493942 [Au] Autor: Pelé A; Falque M; Trotoux G; Eber F; Nègre S; Gilet M; Huteau V; Lodé M; Jousseaume T; Dechaumet S; Morice J; Poncet C; Coriton O; Martin OC; Rousseau-Gueutin M; Chèvre AM [Ad] Endereço: IGEPP, INRA, Agrocampus Ouest, Université de Rennes 1, Le Rheu, France. [Ti] Título: Amplifying recombination genome-wide and reshaping crossover landscapes in Brassicas. [So] Source: PLoS Genet;13(5):e1006794, 2017 May. [Is] ISSN: 1553-7404 [Cp] País de publicação: United States [La] Idioma: eng [Ab] Resumo: Meiotic recombination by crossovers (COs) is tightly regulated, limiting its key role in producing genetic diversity. However, while COs are usually restricted in number and not homogenously distributed along chromosomes, we show here how to disrupt these rules in Brassica species by using allotriploid hybrids (AAC, 2n = 3x = 29), resulting from the cross between the allotetraploid rapeseed (B. napus, AACC, 2n = 4x = 38) and one of its diploid progenitors (B. rapa, AA, 2n = 2x = 20). We produced mapping populations from different genotypes of both diploid AA and triploid AAC hybrids, used as female and/or as male. Each population revealed nearly 3,000 COs that we studied with SNP markers well distributed along the A genome (on average 1 SNP per 1.25 Mbp). Compared to the case of diploids, allotriploid hybrids showed 1.7 to 3.4 times more overall COs depending on the sex of meiosis and the genetic background. Most surprisingly, we found that such a rise was always associated with (i) dramatic changes in the shape of recombination landscapes and (ii) a strong decrease of CO interference. Hybrids carrying an additional C genome exhibited COs all along the A chromosomes, even in the vicinity of centromeres that are deprived of COs in diploids as well as in most studied species. Moreover, in male allotriploid hybrids we found that Class I COs are mostly responsible for the changes of CO rates, landscapes and interference. These results offer the opportunity for geneticists and plant breeders to dramatically enhance the generation of diversity in Brassica species by disrupting the linkage drag coming from limits on number and distribution of COs. [Mh] Termos MeSH primário: Brassica/genética Troca Genética Variação Genética Meiose/genética [Mh] Termos MeSH secundário: Brassica/crescimento & desenvolvimento Genoma de Planta Polimorfismo de Nucleotídeo Único Poliploidia Recombinação Genética [Pt] Tipo de publicação: JOURNAL ARTICLE [Em] Mês de entrada: 1705 [Cu] Atualização por classe: 170607 [Lr] Data última revisão: 170607 [Sb] Subgrupo de revista: IM [Da] Data de entrada para processamento: 170512 [St] Status: MEDLINE [do] DOI: 10.1371/journal.pgen.1006794

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[PMID]: 28297694 [Au] Autor: Torgasheva AA; Borodin PM [Ad] Endereço: Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, and Novosibirsk State University, Novosibirsk, Russia. [Ti] Título: Immunocytological Analysis of Meiotic Recombination in the Gray Goose (Anser anser). [So] Source: Cytogenet Genome Res;151(1):27-35, 2017. [Is] ISSN: 1424-859X [Cp] País de publicação: Switzerland [La] Idioma: eng [Ab] Resumo: Studies on mammals demonstrate wide interspecific variation in the number and distribution of recombination events along chromosomes. Birds represent an interesting model group for comparative analysis of cytological and ecological drivers of recombination rate evolution. Yet, data on variation in recombination rates in birds are limited to a dozen of species. In this study, we used immunolocalization of MLH1, a mismatch repair protein marking mature recombination nodules, to estimate the overall recombination rate and distribution of crossovers along macrochromosomes in female and male meiosis of the gray goose (Anser anser). The average number of MLH1 foci was significantly higher in oocytes than in spermatocytes (73.6 ± 7.8 and 58.9 ± 7.6, respectively). MLH1 foci distribution along individual macrobivalents showed subtelomeric peaks, which were more pronounced in males. Analysis of distances between neighboring MLH1 foci on macrobivalents revealed stronger crossover interference in male meiosis. These data create a framework for future genetic and physical mapping of the gray goose. [Mh] Termos MeSH primário: Gansos/genética Recombinação Homóloga Meiose/genética Oócitos/metabolismo Espermatócitos/metabolismo [Mh] Termos MeSH secundário: Animais Proteínas Aviárias/metabolismo Pareamento Cromossômico Segregação de Cromossomos Cromossomos/genética Troca Genética Feminino Gansos/metabolismo Imuno-Histoquímica Cariótipo Masculino Proteína 1 Homóloga a MutL/metabolismo Estágio Paquíteno Complexo Sinaptonêmico [Pt] Tipo de publicação: JOURNAL ARTICLE [Nm] Nome de substância: 0 (Avian Proteins); EC 3.6.1.3 (MutL Protein Homolog 1) [Em] Mês de entrada: 1709 [Cu] Atualização por classe: 170925 [Lr] Data última revisão: 170925 [Sb] Subgrupo de revista: IM [Da] Data de entrada para processamento: 170316 [St] Status: MEDLINE [do] DOI: 10.1159/000458741

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[PMID]: 28223312 [Au] Autor: Ziolkowski PA; Underwood CJ; Lambing C; Martinez-Garcia M; Lawrence EJ; Ziolkowska L; Griffin C; Choi K; Franklin FC; Martienssen RA; Henderson IR [Ad] Endereço: Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom. [Ti] Título: Natural variation and dosage of the HEI10 meiotic E3 ligase control crossover recombination. [So] Source: Genes Dev;31(3):306-317, 2017 Feb 01. [Is] ISSN: 1549-5477 [Cp] País de publicação: United States [La] Idioma: eng [Ab] Resumo: During meiosis, homologous chromosomes undergo crossover recombination, which creates genetic diversity and balances homolog segregation. Despite these critical functions, crossover frequency varies extensively within and between species. Although natural crossover recombination modifier loci have been detected in plants, causal genes have remained elusive. Using natural accessions, we identified two major recombination quantitative trait loci ( s) that explain 56.9% of crossover variation in Col×Ler F populations. We mapped to semidominant polymorphisms in , which encodes a conserved ubiquitin E3 ligase that regulates crossovers. Null mutants are haploinsufficient, and, using genome-wide mapping and immunocytology, we show that transformation of additional copies is sufficient to more than double euchromatic crossovers. However, heterochromatic centromeres remained recombination-suppressed. The strongest -mediated crossover increases occur in subtelomeric euchromatin, which is reminiscent of sex differences in recombination. Our work reveals that HEI10 naturally limits crossovers and has the potential to influence the response to selection. [Mh] Termos MeSH primário: Proteínas de Arabidopsis/genética Arabidopsis/genética Proteínas Cromossômicas não Histona/genética Troca Genética Dosagem de Genes Meiose/genética [Mh] Termos MeSH secundário: Sequência de Aminoácidos Locos de Características Quantitativas Recombinação Genética Homologia de Sequência de Aminoácidos [Pt] Tipo de publicação: JOURNAL ARTICLE [Nm] Nome de substância: 0 (Arabidopsis Proteins); 0 (Chromosomal Proteins, Non-Histone); 0 (HEI10 protein, Arabidopsis) [Em] Mês de entrada: 1708 [Cu] Atualização por classe: 170825 [Lr] Data última revisão: 170825 [Sb] Subgrupo de revista: IM [Da] Data de entrada para processamento: 170223 [St] Status: MEDLINE [do] DOI: 10.1101/gad.295501.116

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