Loss-of-heterozygosity facilitates a fitness valley crossing in experimentally evolved multicellular yeast

These data sets are generated to investigate a simple evolutionary landscape that arises from underdominance at a single locus where the fitness valley consists of only one less-fit genotype. We make use of an experimental system previous evolved in the laboratory, the Saccharomyces cerevisiae snowflake system. This system was experimentally selected resulting in a significant evolutionary shift, the transition from uni-to-multicellularity in asexual diploid populations. We carried out the phenotypic and fitness characterization of the strains. Additionally, we observed a rapid loss of heterozygosity (LOH) events in the heterozygote strains. Experimental evolution starting with the heterozygote strains suggests that LOH is common both under selection and without selection.  LOH event drive adaptation that may enable rapid evolution in diploid yeast.Â