Fig 4. Fixation regime of compensatory mutations as a function of the selfing rate (σ), the strength of deleterious effect (deleteriousness), the recombination rate between the two loci (r), and the dominance coefficient in double heterozygotes (kc).
Populations with high selfing rates always take the corner path on the fitness landscape (i.e., the deepest point of the fitness valley represented by genotypes that are homozygous for the ancestral allele at one locus, and homozygous for the derived allele at the other locus), while populations with low selfing rates can take the diagonal path (i.e., double heterozygous genotype). The diagonal path may however be counter selected (when kc is relatively high) and unstable (when the recombination rate is relatively high). Note that, for the sake of simplicity, all effects are here presented as discrete categories while they are in fact gradual.