Project description:Transcription profile in YPD media of 48 segregants spores obtained from a cross of the yeast strains S96 and YJM789. These spores are a subset of those published by Mancera et al, Nature, 2008. Two CEL files were mislabelled: eQTL_080822_spore_38B.CEL and eQTL_080826_spore_21C.CEL, actually spores 24A and 8D respectively. The correct spore IDs are in the sample annotation (under StrainOrLine).
Project description:High-throughput techniques for detecting DNA polymorphisms generally do not identify changes in which the genomic position of a sequence, but not its copy number, varies among individuals. To explore such balanced structural polymorphisms, we used array-based Comparative Genomic Hybridization (aCGH) to conduct a genome-wide screen for single-copy genomic segments that occupy different genomic positions in the standard laboratory strain of Saccharomyces cerevisiae (S90) and a polymorphic wild isolate (Y101) through analysis of six tetrads from a cross of these two strains. Paired-end high-throughput sequencing of Y101 validated four of the predicted rearrangements. The transposed segments contained one to four annotated genes each, yet crosses between S90 and Y101 yielded mostly viable tetrads. The longest segment comprised 13.5 kb near the telomere of chromosome XV in the S288C reference strain and Southern blotting confirmed its predicted location on chromosome IX in Y101. Interestingly, inter-locus crossover events between copies of this segment occurred at a detectable rate. The presence of low-copy repetitive sequences at the junctions of this segment suggests that it may have arisen through ectopic recombination. Our methodology and findings provide a starting point for exploring the origins, phenotypic consequences, and evolutionary fate of this largely unexplored form of genomic polymorphism.
Project description:To map meiotic crossovers and noncrossovers across the yeast genome, we genotyped the four spores of 51 tetrads arising from sporulation of a YJM789/S96 hybrid strain. Sporulation was induced, tetrads were dissected, and genomic DNA from each spore was hybridized to microarrays, one array per spore. 12 YJM789 and 13 S96 hybridizations were also performed as a reference for genotyping. To analyze recombination mutants, we also hybridized DNA from 5 tetrads arising from a YJM789/S96 hybrid strain homozygous for a MSH4 deletion, and from 20 spores (6 dyads and 8 single spores) arising from a hybrid homozygous for a MMS4 deletion.
Project description:High-throughput techniques for detecting DNA polymorphisms generally do not identify changes in which the genomic position of a sequence, but not its copy number, varies among individuals. To explore such balanced structural polymorphisms, we used array-based Comparative Genomic Hybridization (aCGH) to conduct a genome-wide screen for single-copy genomic segments that occupy different genomic positions in the standard laboratory strain of Saccharomyces cerevisiae (S90) and a polymorphic wild isolate (Y101) through analysis of six tetrads from a cross of these two strains. Paired-end high-throughput sequencing of Y101 validated four of the predicted rearrangements. The transposed segments contained one to four annotated genes each, yet crosses between S90 and Y101 yielded mostly viable tetrads. The longest segment comprised 13.5 kb near the telomere of chromosome XV in the S288C reference strain and Southern blotting confirmed its predicted location on chromosome IX in Y101. Interestingly, inter-locus crossover events between copies of this segment occurred at a detectable rate. The presence of low-copy repetitive sequences at the junctions of this segment suggests that it may have arisen through ectopic recombination. Our methodology and findings provide a starting point for exploring the origins, phenotypic consequences, and evolutionary fate of this largely unexplored form of genomic polymorphism. Array CGH
Project description:To map post-meiotic segregation (PMS) across the yeast genome, we genotyped the two cells resulting from the first mitotic division of the four spores of 4 tetrads of a YJM789/S96 Saccharomyces cerevisiae hybrid strain. Sporulation was induced, tetrads were dissected, spores let to germinate and the two cells coming from the first mitotic division of each spore were finally dissected. DNA from each of the eight cells in each tetrad was extracted from independent overnight cultures in rich medium and hybridized to microarrays, one array per cell. Each hybridization was used to genotype the corresponding cell and genetic differences between the two cells from the same spore revealed PMS. Therefore there are 32 hybridization files, 2 per spore and 8 per tetrad.