title: Spontaneous mutations in diploid Saccharomyces cerevisiae: more beneficial than expected.
abstract: We performed a 1012-generation mutation-accumulation (MA) experiment in the yeast, Saccharomyces cerevisiae. The MA lines exhibited a significant reduction in mean fitness and a significant increase in variance in fitness. We found that 5.75% of the fitness-altering mutations accumulated were beneficial. This finding contradicts the widely held belief that nearly all fitness-altering mutations are deleterious. The mutation rate was estimated as 6.3 x 10(-5) mutations per haploid genome per generation and the average heterozygous fitness effect of a mutation as 0.061. These estimates are compatible with previous estimates in yeast.
authors.affiliation: Section of Integrative Biology, University of Texas, Austin, Texas 78712, USA.
authors.forename: Sarah B
authors.initials: SB
authors.lastname: Joseph
authors.forename: David W
authors.initials: DW
authors.lastname: Hall
mesh_terms: D016013:Likelihood Functions; D009154:Mutation; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000502:physiology