Data from: The role of pleiotropy in the maintenance of sex in yeast
Hill, Jessica A.; Otto, Sarah P. (2007), Data from: The role of pleiotropy in the maintenance of sex in yeast, Dryad, Dataset, https://doi.org/10.5061/dryad.18
In facultatively sexual species, lineages that reproduce asexually for a period of time can accumulate mutations that reduce their ability to undergo sexual reproduction when sex is favorable. We propagated Saccharomyces cerevisiae asexually for ~800 generations, after which we measured the change in sexual ﬁtness, measured as the proportion of asci observed in sporulation medium. The sporulation rate in cultures propagated asexually at small population size declined by 8%, on average, over this time period, indicating that the majority of mutations that affect sporulation rate are deleterious. Interestingly, the sporulation rate in cultures propagated asexually at large population size improved by 11%, on average, indicating that selection on asexual function effectively eliminated most of the mutations deleterious to sporulation ability. These results suggest that pleiotropy between mutations’ effects on asexual ﬁtness and sexual ﬁtness was predominantly positive, at least for the mutations accumulated in this experimental evolution study. A positive correlation between growth rate and sporulation rate among lines also pro- vided evidence for positive pleiotropy. These results demonstrate that, at least under certain circum- stances, selection acting on asexual ﬁtness can help to maintain sexual function.