Southern European groups (SEE, SCE, SDN, SWE, and BA) on the other hand derive ancestry from African and Near Eastern World Regions. In particular, ancestry from groups most similar to contemporary populations from in and around the Levant (lev; which we define as the World Region containing individuals from Syria, Palestine, Lebanon, Jordan, Saudi, Yemen, and Egypt) is present across Italy (SCE), Sardinia (SDN), France and Spain (SWE), and Armenia (IA; Figure 2B). Interestingly, North (nafII) and West (waf) African ancestry is also seen entering Southern Europe, suggesting a key role for the Mediterranean in supporting gene flow back into Europe [8, 26, 27]. Dates for the influx of this admixture are broad and generally fall within the first millennium CE (Figure 3B) although are more recent in BA and SWE, including French (frenc24: 728 CE [424–1011 CE]) and Spanish (spani27: 1042 CE [740–1201 CE]; spani9: 668 CE [286–876 CE]) clusters, consistent with migrations associated with the Arabic Conquest of the Iberian peninsula [8, 11, 28] and earlier movements in and around Italy [29].
(A) For each geographic sampling location, we estimated the proportion of ancestry coming from outside of West Eurasia by averaging GLOBETROTTER’s admixture inference across individuals from a sampling location. The sampling locations of each point are shown in Figure S4A; Caucasus populations are spread out to aid visibility. Points are stacked vertically in cases where multiple ancestries are present in a population.
(B) Copying vectors of 82 West Eurasian fineSTRUCTURE clusters projected onto PCA based on the copying vectors of 1,000 West Eurasian individuals (faded colors; symbols and colors are as in Figure 1B); lines link World Region admixture sources to the clusters in which admixture from them is inferred.
(C) Gene flow within West Eurasia is shown by lines linking the best-matching donor group to the sources of admixture with recipient clusters (arrowhead). Line colors represent the regional identity of the donor group, and line thickness represents the proportion of DNA coming from the donor group. Ranges of the dates (point estimates) for events involving sources most similar to selected donor groups are shown.
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