To infer estimates of male and female contributions from each ancestral population, we estimated the male and female fractions of ancestry that total the genome-wide estimates and minimize the mean square error of the X chromosome ancestry estimates. We assume that overall male and female contributions are each 50% (∑popfpop,male=0.5 and ∑popfpop,female=0.5). We assume that the total contribution from males and females of a population gives rise to the autosomal ancestry fraction (fpop,male + fpop,female = autopop). We then compute, via a grid search, the predicted X chromosome estimates from fpop,male, fpop,female for each pop∈{African,NativeAmerican,European}, which are calculated, as in Lind et al.,6 asXˆpop=fpop,male+2⋅fpop,female0.5⋅1+0.5⋅2=fpop,male+2⋅fpop,female1.5