Figure 2

Evolutionary outcomes. Evolutionary outcomes depend heavily on k (the level of constitutive expression across both loci) and h (the steepness of the sigmoid function σ of Eq (2)) which jointly determine the change in gene expression at the D locus (${\widehat{S}}_D$) caused by the A regulatory allele at the R locus. For each mutation pair, we map regions in which there are transitions in sex determination locus (T), recruitment without transition (R), and changes in heterogamety (H).