tailieunhanh - Báo cáo y học: "Genome-wide survey of post-meiotic segregation during yeast recombinati"

Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học Wertheim cung cấp cho các bạn kiến thức về ngành y đề tài: Genome-wide survey of post-meiotic segregation during yeast recombination. | Mancera et al. Genome Biology 2011 12 R36 http 2011 12 4 R36 Genome Biology RESEARCH Open Access Genome-wide survey of post-meiotic segregation during yeast recombination Eugenio Mancera1t Richard Bourgon2 3t Wolfgang Huber1 and Lars M Steinmetz1 Abstract Background When mismatches in heteroduplex DNA formed during meiotic recombination are left unrepaired post-meiotic segregation of the two mismatched alleles occurs during the ensuing round of mitosis. This gives rise to somatic mosaicism in multicellular organisms and leads to unexpected allelic combinations among progeny. Despite its implications for inheritance post-meiotic segregation has been studied at only a few loci. Results By genotyping tens of thousands of genetic markers in yeast segregants and their clonal progeny we analyzed post-meiotic segregation at a genome-wide scale. We show that post-meiotic segregation occurs in close to 10 of recombination events. Although the overall number of markers affected in a single meiosis is small the rate of post-meiotic segregation is more than five orders of magnitude larger than the base substitution mutation rate. Post-meiotic segregation took place with equal relative frequency in crossovers and non-crossovers and usually at the edges of gene conversion tracts. Furthermore post-meiotic segregation tended to occur in markers that are isolated from other heterozygosities and preferentially at polymorphism types that are relatively uncommon in the yeast species. Conclusions Overall our survey reveals the genome-wide characteristics of post-meiotic segregation. The results show that post-meiotic segregation is widespread in meiotic recombination and could be a significant determinant of allelic inheritance and allele frequencies at the population level. Background In sexually reproducing organisms homologous chromosomes exchange genetic information through meiotic recombination. This process which occurs in most eukaryotes is an important .