NEW YORK – An ancient genome analysis centered on dozens of Neolithic and Bronze Age individuals from northern China suggests that regions linked to agriculture and crop domestication experienced corresponding influxes of new ancestry from other areas.
"Although the genetic changes in each region differ in timing and intensity, each shift is correlated with changes in subsistence strategy," first author Chao Ning, a researcher affiliated with Jilin University and the Max Planck Institute for the Science of Human History (MPI-SHH), said in a statement.
Ning and colleagues from China, Germany, and Korea used shotgun sequencing to screen for ancient DNA in more than 100 samples from archeological sites in the West Liao River Basin and Yellow River Basin where cereal crop domestication — particularly dryland millet farming — took place. They also assessed samples from the Amur River region, sites in Shaanxi province, and archeological locations in the Inner Mongolia Autonomous region.
From there, the team focused in on remains from 55 ancient individuals dated at around 1,700 to 7,500 years old for deeper sequencing, generating genomes covered to an average depths of 0.03- to more than 7.5-fold from the Amur River, West Liao River, and Yellow River regions. The findings, published in Nature Communications on Monday, pointed to ancestry shifts in the latter two areas that appeared to correspond closely with subsistence strategy changes.
In the West Liao River region's Hongshan culture, for example, the team documented a jump in ancestry associated with Yellow River and Amur River populations that appeared to track with shifts to millet farming during the late Neolithic period and more pastoral lifestyles in the Bronze Age, respectively. In the Amur River basin itself, though, populations remained genetically consistent over the time period considered.
Populations in the Yellow River basin area, home to the Yangshao culture, showed a distinct population pattern marked by a more gradual rise in ancestry resembling Yangtze River basin populations in southern China starting in the middle Neolithic Period, the researchers reported, along with new Southeast Asian ancestry. They speculated that these population interactions may have occurred during migrations that brought rice farming further north, but cautioned that that possibility must be explored further.
Co-senior and co-corresponding author Choongwon Jeong, a biological sciences researcher affiliated with Seoul National University who previously worked as a geneticist in the Eurasia3angle research group, said in a statement that "our current dataset needs ancient genomes from people who brought rice agriculture into northeast China, such as ancient farmers from the Shandong and Lower Yangtze River regions."
"[N]evertheless," Jeong said, "our study is a major step forward in understanding how this region developed."
The work was done through the Eurasia3angle research group, which is funded by the European Research Council and led by MPI-SHH archaeologist and linguist Martine Robbeets, a co-senior author on the new study.
Robbeets noted in a statement that the new findings "fuel the debate on the historical correlation between archaeological cultures, languages, and genes," since past research suggests the Trans-eurasian language family may have originated in the West Liao River Basin, while the Yellow River Basin has typically been associated with a Sino-Tibetan language family.
"Future studies of ancient genomes across China, particularly the genomes of the first farmers, will be critical to test the representativeness of the genomes reported in this study, to understand the genetic changes we detected at finer genetic, archaeological, and geographic scales, and to test the evolutionary correlation between archaeological cultures, languages, and genes," the authors concluded.