Figure 3.

Inference of Admixture Models from Genomic Regions with Little or No Selective Constraint

(A) Schematic illustration of the one- and two-pulse models of Neandertal introgression. The majority of introgression occurred in the common ancestor of all non-Africans (m₁), and a smaller additional amount of introgression occurred in East Asians (m₂).

(B) Schematic illustration of the one-pulse and European-dilution models. All Neandertal introgression occurred in the common ancestor of Europeans and East Asians (m₁), and a substantial portion of modern-day European ancestry (A_X) derived from a second population (X) with no Neandertal ancestry.

Below each demographic model are histograms of m₂/ m₁ (left; the proportion of additional introgression into East Asians) and A_X (right; the proportion of European ancestry derived from population X) as estimated by 30,000 simulations and ABC analysis (adjusted values of 1,500 accepted simulations are shown). Dashed lines demark 95% confidence intervals (CIs). Black arrows show the expected values of m₂/ m₁ (0) and A_X (0.023)¹² under the one-pulse model.