An analysis of ancient human genomic data suggests that Copper Age farmers and steppe pastoralists may have interacted 1,000 years earlier than previously thought. The findings, published in Nature, may aid our understanding of the demise of the Copper Age and the expansion of pastoralist groups around 3,300 BC.
Previous analyses of ancient genomic data have suggested that two major genetic turnover events occurred in Western Eurasia; one associated with the spread of farming around 7,000-6,000 BC and a second resulting from the expansion of pastoralist groups from the Eurasian steppe starting around 3,300 BC. The period between these two events, the Copper Age, was characterized by a new economy based on metallurgy, wheel and wagon transportation, and horse domestication. However, what happened between the demise of Copper Age settlements (around 4,250 BC) and the expansion of pastoralists is not well understood.
According to the paper, the researchers analysed genetic data from 135 ancient individuals, dating to between 5,400 and 2,400 BC, from eight sites across southeastern Europe and the northwestern Black Sea region. While there was genetic continuity between the Neolithic and Copper Age groups, from around 4500 BC groups from the northwestern Black Sea region carried varying amounts of ancestry from Copper Age and steppe-zone populations, the authors write.
They suggest that this finding shows that the groups had cultural contact and mixed nearly 1,000 years earlier than previously thought. The transfer of technology between farmers and transitional hunters from different geographical zones was integral to the rise, formation and expansion of pastoralist groups around 3300 BC, the authors propose.
“A principal finding from our study indicates early contact and admixture between Copper Age farming groups from southeastern Europe and Eneolithic groups from the steppe zone in today’s southern Ukraine, possibly starting in the 5,500 BC when settlement densities shifted further north,” they write.
According to the authors, the early admixture during the Eneolithic appears to be local to the NW Black Sea region of the fourth millennium BC and did not affect the hinterland in southeastern Europe. “In fact, the Early Bronze Age individuals from Yunatsite and Pietrele do not show traces of steppe-like ancestry but instead a resurgence of hunter-gatherers ancestry observed widely in Europe during the fourth millennium BC,” they write.