Outcrossing, mitotic recombination, and life-history tradeoffs shape genome evolution in Saccharomyces cerevisiae

We sequenced the genomes of ten (10) diploid environmental isolates and one (1) laboratory strain of the budding yeast Saccharomyces cerevisiae. We find that many budding yeast strains have high levels of genomic heterozygosity, from which we infer that outcrossing plays an important role in shaping genome architecture and evolution in this species. In addition to elevated levels of heterozygosity, many strains exhibit large genomic regions of loss-of-heterozygosity (LOH), suggesting that mitotic recombination also occurs at a relatively high rate.