Fig. 4.

Overdominance of diploid-evolved heterozygous mutations. Average fitness of LOH of putative beneficial mutations was determined by driving LOH in the evolved background (a) or by introgressing the evolved mutations into the ancestral background (b). Small markers represent individual fitness values from independently constructed strains and large markers represent the respective averages. The homozygous ancestral alleles are annotated by two open circles, heterozygous by one open and one white and homozygous evolved by two white circles. Open big circles in (b) annotate final segregant backcrossed to haploid version of the ancestor and filled circles annotate intra-ascus matings of the final cross.