Fig. 2: The effect of SBG expression on shared polymorphism across the three populations.

This figure shows predicted values (± s.e.m.) of the probability that a gene harbours ≥1 SNP that shows intermediate frequency polymorphism in all three populations across bins, from a generalized linear model (binomial errors and a logit link function) accounting for the effects of gene length and SNP density. The effect of SBG category on shared polymorphism, accounting for these covariates, was highly significant (Wald χ27 = 24.93, P < 0.001). Sample size per bin is n = 592–656 genes.