Normalized progeny viability in the permissive environment for all matings in Experiment L (a) and Experiment H (b). Matings between lineages evolved in parallel environments (PE matings, n = 24) or divergent environments (DE matings, n = 36) are in grey or white, respectively. Mean progeny viability for each class was normalized over the grand mean for each assay point. Asterisks indicate significance differences between mating classes, as determined by Fisher exact tests (two-tailed) using ascospore germination/non-germination frequencies. Mean n per assay > 10,000 ascospores scored.