NEW YORK (GenomeWeb) – The first farmers in Anatolia were descendants of local hunter-gatherers, according to a new ancient DNA study.
Farming first emerged in the Fertile Crescent about 11,000 years ago, before spreading from there to what is now Turkey by 8,300 BC. Anatolian farmers then spread the technology — and their genes — to Europe, replacing much of the local hunter-gatherers. But it has been unclear whether a similar scenario played out in Anatolia with farming arriving with new migrants or with hunter-gatherers there adopting the new practice.
An international team of researchers has generated genome-wide SNP data on eight prehistoric individuals, including an Epipaleolithic Anatolian hunter-gatherer, five early Neolithic Aceramic Anatolian farmers, and two early Neolithic farmers from the Levant. As they reported in Nature Communications today, the researchers found that the Neolithic Anatolians derived a large portion of their ancestry from the Epipaleolithic Anatolian, indicating genetic continuity in the region.
"Our results provide additional, genetic support for previous archaeological evidence that suggests that Anatolia was not merely a stepping stone in a movement of early farmers from the Fertile Crescent into Europe," co-senior author Choongwon Jeong from the Max Planck Institute of the Science of Human History said in a statement. "Rather, it was a place where local hunter-gatherers adopted ideas, plants, and technology that led to agricultural subsistence."
The researchers combined the new ancient DNA data they generated with previously published datasets from 587 ancient individuals and 254 present-day populations. Through a principal components analysis, the researchers noted that the Anatolian hunter-gatherers, who lived about 13,300 years BC, clustered with the two Neolithic Aceramic Anatolian farmers and later Neolithic Ceramic Anatolian farmers. In an analysis using the Admixture algorithm, the researchers found those three populations to be a mix of ancestries maximized within Natufians, a sedentary hunter-gatherer population from the Levant, and western European hunter-gatherers.
Using formal statistical frameworks, the researchers further examined the genetic profiles of their three Anatolian populations. Based on this, they found that Anatolian hunter-gatherers were distinct from western European hunter-gatherers and from Epipaleolithic/Neolithic Levantine populations, but shared some genetic affinity with each. This, the researchers noted, indicated that there were Near Eastern and European hunter-gather-related ancestries in central Anatolia, during the late Pleistocene.
Neolithic Aceramic Anatolian farmers, meanwhile, shared slightly more ancestry with early Holocene populations from Iran or the Caucasus and with present-day south Asians, who are also thought to have Iranian-Caucasus ancestry.
When they modeled the Neolithic Aceramic Anatolian farmers' ancestry, they noted the best fit suggested that Anatolian hunter-gatherers provided the most — about 90 percent — of their ancestry. This, the researchers added, indicates there was long-term genetic stability in central Anatolia, even as the subsistence strategy changed.
The later Neolithic Ceramic Anatolian farmers, though, shared more alleles with the early Holocene Levantines than the Neolithic Aceramic Anatolian farmers did. Still, the researchers noted that the Neolithic Aceramic Anatolian farmers contributed about three-quarters of the Neolithic Ceramic Anatolian farmers' ancestry. This, they added, suggests there was gene flow between the Levant and Anatolia in the early Neolithic.
"There are some large gaps, both in time and geography, in the genomes we currently have available for study," senior author Johannes Krause from Max Planck said in a statement. "This makes it difficult to say how these more subtle genetic interactions took place — whether it was through short-term large movements of people, or more frequent but low-level interactions."