Pith: My deduction is that for a typical trait varied due to drift phenotypic variation is roughly ~ quantitative genetic variance*h^2, where quantitative genetic variance is roughly 2 SNP Fst; thus, assuming a typical narrow heritability of 0.5, one gets phenotypic variation ~ SNP Fst. And this is why the (phenotypic) craniometric continental eta-squared is ~ 0.12.