The origin and early dispersal of Transeurasian languages, including, among others, Japanese, Korean, Tungusic, Mongolic and Turkic, is among the most disputed issues of Asian prehistory. Although many of the commonalities between these languages are due to borrowing, recent studies have shown evidence supporting the classification of Transeurasian as a genealogical group, or a group of languages that emerged from a common ancestor.
A new paper published in the journal Nature by an international team that includes researchers from the University of Auckland provides interdisciplinary support for the "Farming Hypothesis" of language dispersal, tracing Transeurasian languages back to the first farmers moving across Northeast Asia beginning in the Early Neolithic – roughly between 8-10 thousand years ago.
Using newly sequenced genomes, an extensive archaeological database, and a new dataset of vocabulary concepts for 98 languages, the researchers triangulate the time-depth, location and dispersal routes of ancestral Transeurasian speech communities.
The evidence from linguistic, archeological and genetic sources indicates that the origins of the Transeurasian languages can be traced back to the beginning of millet cultivation and the early Amur gene pool in the region of the West Liao River.
During the Late Neolithic, millet farmers with Amur-related genes spread into contiguous regions across Northeast Asia. In the millennia that followed, speakers of the daughter branches of Proto-Transeurasian admixed with Yellow River, western Eurasian and Jomon populations, adding rice agriculture, western Eurasian crops and pastoralist lifeways to the Transeurasian package.
The linguistic evidence used to triangulate came from a new dataset of more than 3,000 cognate sets representing over 250 concepts in nearly 100 Transeurasian languages. From this, researchers were able to construct a phylogenetic tree which shows the roots of the Proto-Transeurasian family reaching back over 9,000 years before the present to millet farmers living in the region of the West Liao River.
The new study also reports the first collection of ancient genomes from Korea, the Ryukyu Islands and early cereal farmers in Japan. Combining their results with previously published genomes from East Asia, the team identified a common genetic component called "Amur-like ancestry" among all speakers of Transeurasian languages.
They were also able to confirm that the Bronze Age Yayoi period in Japan saw a massive migration from the continent at the same time as the arrival of farming. Taken together, the study's results show that, although masked by millennia of extensive cultural interaction, Transeurasian languages share a common ancestry and that the early spread of Transeurasian speakers was driven by agriculture.
University of Auckland author on the paper, Dr Remco Bouckaert from the School of Computer Science says the tools, or phylogenetic methods, used in the study were largely developed by a team at the University. "I've been working on cultural evolution for a decade and am really pleased to see these quantitative techniques increasingly adapted and applied to research in the life sciences."
The researchers say more ancient DNA, more etymological research and more archaeobotanical research will further deepen understanding of human migrations in Neolithic Northeast Asia and untangle the influence of later population movements, of which many were pastoralist in nature.
