UNASSIGNED: Much of our knowledge of the @entity410 effects of new mutations has been gained from @entity409 ( @entity409 ) experiments. Yet the @entity410 effect of single mutations is rarely measured in @entity409 experiments. This raises several issues, notably for inferring epistasis for @entity410 . The acceleration of @entity410 decline in @entity409 lines has been taken as evidence for @entity61902 , but establishing the role of epistasis requires measuring the @entity410 of genotypes carrying known numbers of mutations. Otherwise, accelerating @entity410 loss could be explained by increased genetic mutation rates. Here we segregated mutations accumulated over 4800 generations in haploid and diploid @entity409 lines of the @entity375 @entity375 . We find no correspondence between an accelerated @entity410 decline and @entity61902 among deleterious mutations in haploid lines. Pairs of mutations showed no overall epistasis. Furthermore, several lines of evidence indicate that genetic mutation rates did not increase in the @entity409 lines. Crucially, segregant @entity410 analyses revealed that @entity409 accelerated in both haploid and diploid lines, even though the @entity410 of diploid lines was nearly constant during the @entity409 experiment. This suggests that the accelerated @entity410 decline in haploids was caused by cryptic environmental factors that increased mutation rates in all lines during the last third of the lines transfers. In addition, we provide new estimates of deleterious mutation rates, including lethals, and highlight that nearly all the mutational load we observed was due to one or two mutations having a large effect on @entity410 .

Accelerating Mutational Load Is not Due to Synergistic Epistasis or Mutator Alleles in Mutation Accumulation Lines of XXXX .

@entity61902 :: ('MESH:C566508', 'Disease') :: ['synergistic epistasis'] @entity375 :: ('4932', 'Species') :: ['yeast', 'Saccharomyces cerevisiae'] @entity410 :: ('MESH:D012640', 'Disease') :: ['fitness'] @entity409 :: ('MESH:D008107', 'Disease') :: ['MA', 'mutation accumulation']
@entity375 :: (4932,Species) :: ['Yeast']
