The Molecular Evolution of Animal Reproductive Tract Proteins: What Have We Learned from Mating-System Comparisons?
Figure 2
Consequences of sexual selection. (a) Regression of log(testis mass) on log(body mass). Polyandrous species (open circles) tend to have large testes for their body size, and hence fall above the regression line, while monandrous species (diamonds) tend to have relatively small testis. Data are from [47]. (b) Regression of ω on residual testis mass for SEMG2, showing that the rate of protein evolution increases with relative testis size. Estimates of ω are from [56], and testis mass residuals were calculated from panel (a).
