[FONT="]Eastern European hunter-gatherer ancestry as a marker for Yamnaya steppe pastoralist ancestry is absent in a newly reported Middle Minoan period individual from Zakros on the eastern edge of Crete. This individual’s ancestry is generally similar to those previously published ([/FONT]13[FONT="]), but with significant Levantine admixture (30.5 ± 9.1%), which is consistent with her either being a migrant to the island from the east or part of a structured Cretan population whose past ethnic diversity was noted as early as the [/FONT]Odyssey of Homer (Hom. Od. 19.172-177).
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Both Caucasus and Eastern European hunter-gatherer–related ancestry increased in the Bronze Age in the Aegean just as the Anatolian-related ancestry decreased (Fig. 1), with Mycenaean Greeks having 21.2 ± 1.3% Caucasus hunter-gatherer ancestry and 4.3 ± 1.0% Eastern European hunter-gatherer ancestry. Given the evenly balanced proportions of these components in the Yamnaya and the “high steppe” cluster from the Balkans (1), it can be assumed that the Eastern European hunter-gatherer component in the Aegean was not introduced there on its own but rather was accompanied by an approximately matching amount of Caucasus hunter-gatherer ancestry, thus leaving a remainder of ~21.2 − 4.3 = 16.9% Caucasus hunter-gatherer. This allows us to infer that steppe migrants admixed with a population whose composition must have included 16.9100−2×4.3 or ~18.5% Caucasus hunter-gatherer–related ancestry. Notably, the estimated proportion of Caucasus hunter-gatherer ancestry in Minoans is virtually identical at 18.3 ± 1.2%.
Thus, our analyses resolve the question of the origins of the Late Bronze Age population by strongly supporting one of two previously proposed hypotheses (4)—that Mycenaeans were the outcome of admixture of descendants of Yamnaya-like steppe migrants with a Minoan-like substratum, rather than the hitherto plausible alternative scenario of an Anatolian Neolithic–like substratum admixing with an Armenian-like population from the east. This alternative scenario is further contradicted by the fact that pre–Mycenaean period individuals belonging to the Early Bronze Age from the islands of the Cyclades and Euboea in Southern Greece in ~2500 BCE (12) had 21.2 ± 1.7% Caucasus hunter-gatherer–related ancestry (12), consistent with our inferred proportion and providing direct evidence for the predicted Minoan-like substratum (4).
The fact that Mycenaeans can be modeled as a mixture in an ~1:10 ratio of a Yamnaya-like steppe-derived population and a Minoan- or Early Bronze Age–like Aegean population suggests that any contribution of geographically intermediate populations (between the steppe and the Aegean) to the formation of Mycenaeans was minor. This conclusion is further supported by the following: (i) the lower (~5%) Caucasus hunter-gatherer ancestry in the Neolithic of the Balkans compared with the ~20% inferred for the Aegean substratum (1), (ii) the near absence of Balkan hunter-gatherer (fig. S1) ancestry in the Aegean in contrast to other Southeastern European populations (~10%) (1), and (iii) the presence of Yamnaya-like individuals with minimal local ancestry—immediately to the north of the Aegean—in Albania and Bulgaria during the Early Bronze Age (1). Whatever the genetic makeup of people mediating the spread of steppe ancestry into the ancestors of Mycenaeans, the genetic impact of steppe on Aegean populations was quantitatively minor. We estimate the Yamnaya-related steppe ancestry proportion in Mycenaeans to be ~⅓ of the level of that in the Balkans to the north, ~½ of that in Armenia in the east, and ~⅕ to ⅛ of that of populations of Central/Northern Europe associated with the Bell Beaker and Corded Ware cultures (1).
