Estimation of African ancestry using <i>f<sub>4</sub> Ancestry Estimation</i>.
Domain:
healthcareRecord type:
f4 Ancestry Estimation computes the quantity [(San-Papuan).(X–CEU)/[(San-Papuan).(YRI-CEU)]; where X = any West Eurasian population. The denominator is proportional to the genetic drift m that occurred in the ancestors of West or East Africans since their divergence from San but prior to their divergence from West Eurasians (intersection of red and orange lines). The numerator is proportion to p*(Ancestral Africans-YRI) + (1-p)*(Ancestral Europeans-CEU). Since the branches connecting (San, Papuan) and (CEU, X) do not overlap each other, the quantity (1-p)*(X-CEU) = 0 and hence the numerator is expected to equal pm. Thus, the ratio of the numerator and denominator is expected to equal p (Ancestral African mixture proportion). This figure is adapted from reference [21], where we first developed f4 Ancestry Estimation, and where we reported computer simulations demonstrating its robustness.