NEW YORK – Using an integrated analysis of genetic, archaeological, and linguistic data, a team from Germany, France, China, and other international centers has found evidence that ancient agricultural groups initially spread so-called Transeurasian languages — encompassing the Japonic, Koreanic, Tungusic, Mongolic, and Turkic linguistic families — throughout Northeast Asia.
"Challenging the traditional pastoralist hypothesis for Transeurasian origins, our research brings the case of the Transeurasian languages in line with the farming/language dispersal hypothesis, which posits that many of the world’s major language families owe their primary dispersals to the adoption of agriculture by their early speakers," first author Martine Robbeets, a comparative linguistic researcher at the Max Planck Institute for the Science of Human History, said in an e-mail.
For a paper published in Nature on Wednesday, the researchers sequenced the genomes of 23 ancient individuals from Neolithic or Bronze Age sites in what is now Russia, Korea, and Japan, analyzing the data alongside published sequences from other ancient individuals in the region. To that, they added almost 3,200 cognate linguistic datasets spanning hundreds of vocabulary clues from 98 Transeurasian languages, as well as archaeological insights from 255 Neolithic or Bronze Age sites in Northeast Asia.
Together, these data made it possible to spell out dynamic Neolithic interactions between populations with Amur, Yellow River, and Jomon ancestry in Russia, Mongolia, China, Korea, and Japan, in relation to language spread and to the farming of crops such as millet and rice. Stretching back further, the team saw signs that farming populations from Northeast China migrated to Japan and Korea an estimated 9,000 years ago, bringing the roots of Transeurasian language with them.
"Taken by itself, a single discipline alone cannot conclusively resolve the question about farming/language dispersals, but taken together the three disciplines increase the credibility and validity of this scenario," Robbeets explained. "Aligning the evidence offered by the three disciplines, we gained a more balanced and richer understanding of Transeurasian migration than each of the three disciplines could provide us with individually."
In particular, the data linked language spread to agricultural population movements during the Early Neolithic period. Although shared ancestry stemming from such migrations may have been masked to some extent by post-Bronze Age interactions, the investigators explained, representatives from the Transeurasian language-speaking groups carried "Amur-like ancestry" suspected of representing hunter-gatherers found in the region prior to the advent of farming.
"Triangulation of linguistic, archaeological, and genetic evidence shows that the origins of the Transeurasian languages can be traced back to the beginning of millet cultivation and the early Amur gene pool in Neolithic Northeast Asia," the authors reported. "The spread of these languages involved two major phases that mirror the dispersal of agriculture and genes."
The combined genetic, archaeological, and linguistic data also revealed more detailed population dynamics in specific places over time. With the first ancient genomes from the Korean Peninsula, for example, the researchers detected ancestry from a Jomon population that was previously tied to Japan.
One ancient female from the Yokchido site in Korea had 95 percent Jomon ancestry, Robbeets noted, suggesting she may have been descended from a recent migrant from Japan, while two other Koreans from the Neolithic had 10 to 20 percent Jomon ancestry.
"Surprisingly, several of our Neolithic samples from Korea had a significant amount of Jomon DNA characteristic of Japan in the Neolithic age," she said, consistent with "broader links between the populations of the peninsula and archipelago at the time."
Jomon ancestry also turned up in newly sequenced ancient individuals from the Southern Ryukyus island region, which appeared to be connected to populations in Japan rather than to Taiwan as previously suspected. Jumping ahead to the Bronze Age, meanwhile, the results pointed to more recent migrations from continental sites into Japan.
From these and other findings, the authors concluded that the farming/language dispersal model offers the most plausible model for language spread during the Neolithic, Robbeets explained, though it remains likely that subsequent Bronze Age migrations involved Transeurasian language speakers from more pastoral groups.
"[T]here was far more to the creation of the Transeurasian language family, as an ultimate whole, than just one primary Neolithic pulse of migration," she said, adding that future research may help to further refine the view of language spread over time, along with the unexpected population interactions identified in the current analyses.
"We only lifted a tip of the veil," Robbeets said. "More data from ancient DNA, more etymological research, and more archaeobotanical research will further deepen our understanding of human migrations in Northeast Asia in the future."
In a related News and Views article in Nature, Australian National University archaeology and anthropology researcher Peter Bellwood noted that the study "provides computational linguistic support for the existence of a unified Transeurasian language family, a concept that has divided linguists" and "puts the focus on the initial development of agriculture in northeastern Asia as being the underlying driver of the expansion of Transeurasian languages, rather than the later development of specialized pastoralism in central Asia."