Shifts in the Genetic Landscape of the Western Eurasian Steppe Associated with the Beginning and End of the Scythian Dominance

The Early Iron Age nomadic Scythians have been described as a confederation of tribes of different origins, based on ancient DNA evidence [1–3]. It is still unclear how much of the Scythian dominance in the Eurasian Steppe was due to movements of people and how much reflected cultural diffusion and elite dominance. We present new whole-genome sequences of 31 ancient Western and Eastern Steppe individuals, including Scythians as well as samples pre- and postdating them, allowing us to set the Scythians in a temporal context (in the Western, i.e., Ponto-Caspian Steppe). We detect an increase of eastern (Altaian) affinity along with a decrease in eastern hunter-gatherer (EHG) ancestry in the Early Iron Age Ponto-Caspian gene pool at the start of the Scythian dominance. On the other hand, samples of the Chernyakhiv culture postdating the Scythians in Ukraine have a significantly higher proportion of Near Eastern ancestry than other samples of this study. Our results agree with the Gothic source of the Chernyakhiv culture and support the hypothesis that the Scythian dominance did involve a demic component. •31 new ancient genomes help compare the Scythians to pre- and postdating cultures•Scythian dominance brought along an increase of eastern ancestry across the steppe•Results imply some demic diffusion in the spread of the Scythian culture•Genetic makeup agrees with the Gothic source of post-Scythian Chernyakhiv culture Järve et al. present 31 ancient Scythians and samples from pre- and postdating cultures from the Eurasian Steppe. An increase of eastern ancestry in the steppe during the Scythian period supports some demic diffusion in the spread of the Scythian culture. The genetic makeup of post-Scythian Chernyakhiv individuals agrees with their Gothic source.