The population structure of the ancient Near East was not independent of that of Europe (Supplementary Information, Section 4), as evidenced by the highly significant (Z = -8.9) f4 statistic (Iran_N, Natufian: WHG, EHG), which suggests gene flow in the "Northeast" (Neolithic Iran/EHG) and "Southwest" (Levant/WHG) interaction spheres (Figure 4d). This interdependence of European and Middle Eastern origins may have been mediated by geographically uncovered intermediate populations that bring ancestry to both regions.