New research answers a long-debated question among anthropologists, archaeologists and geneticists: when farmers first arrived in Europe, how did they interact with existing hunter-gatherer groups? Prior studies have suggested these early Near Eastern farmers largely replaced the pre-existing European hunter-gatherers. Did the farmers wipe out the hunter-gatherers, through warfare or disease, shortly after arriving? Or did they slowly out-compete them over time? The current study, published in Nature, suggests that these groups likely coexisted side-by-side for some time after the early farmers spread across Europe. The farming populations then slowly integrated local hunter-gatherers, showing more assimilation of the hunter-gatherers into the farming populations as time went on.
The Copper Age skull of Vörs (Hungary) with a copper diadem [Credit: Tibor Kádas, Mária Bondár] |
Numerous studies have shown that early farmers from all over Europe, such as the Iberian Peninsula, southern Scandinavia and central Europe, all shared a common origin in the Near East. This was initially an unexpected finding given the diversity of prehistoric cultures and the diverse environments in Europe. Interestingly, early farmers also show various amounts of hunter-gatherer ancestry, which had previously not been analyzed in detail.
Sampling of petrous bone from a human skull by Balázs G. Mende [Credit: Institute of Archaeology RCH HAS, Budapest] |
"We find that the hunter-gatherer admixture varied locally but more importantly differed widely between the three main regions," says Mark Lipson, a researcher in the Department of Genetics at Harvard Medical School and co-first author of the paper. "This means that local hunter-gatherers were slowly but steadily integrated into early farming communities."
"One novelty of our study is that we can differentiate early European farmers by their specific local hunter-gatherer signature," adds co-first author Anna Szécsényi-Nagy of the Hungarian Academy of Sciences. "Farmers from Spain share hunter-gatherer ancestry with a pre-agricultural individual from La Braña, Spain, whereas farmers from central Europe share more with hunter-gatherers near them, such as an individual from the Loschbour cave in Luxembourg. Similarly, farmers from the Carpathian Basin share more ancestry with local hunter-gatherers from their same region."
An Early Neolithic grave from Bátaszék (Hungary), which was also part of the DNA analyses [Credit: Anett Osztás] |
"We found that the most probable scenario is an initial, small-scale, admixture pulse between the two populations that was followed by continuous gene flow over many centuries," says senior lead author David Reich, professor of Genetics at Harvard Medical School.
These results reflect the importance of building thorough, detailed databases of genetic information over time and space, and suggest that a similar approach should be equally revealing elsewhere in the world.
Source: Max Planck Institute for the Science of Human History [November 09, 2017]