Figure 1.

Sex-related partitions of the gene pool. The gene pool is independently subdivided into female (circles) and male (squares) niches and into matrigenic (pink) and patrigenic (blue) niches. Gene flow between the environments is represented by arrows. Thin arrows represent 50% gene flow in each generation. Thick arrows represent 100% gene flow. (A) Autosomal alleles experience all four environments. (B) Y-linked genes experience only the patrigenic male environment. X-linked genes are excluded from this environment.