The genome-wide analysis of data from populations from 94 countries could provide insights into the peopling of Japan. The findings are published in the journal Scientific Reports.
The Jomon people were the sole inhabitants of the Japanese islands for more than 10,000 years until the isolation ended around 2,000 years ago with the arrival of the Yayoi people, immigrants from the continent, carrying rice farming technology and metal tools. But the genetic contribution of the Jomon to the contemporary Japanese population has been hard to determine because all modern Japanese populations are subject to admixture, or gene mixing, at various levels, and no one of exclusively Jomon ancestry now exists.
Yungang He and colleagues report the quantitative analysis of single-letter variants in the genetic code (single nucleotide polymorphisms) in genome-wide data from 94 worldwide populations, in order to infer the origin of the Jomon and to estimate the relative contributions of the Jomon and the Yayoi to the genetic pool in contemporary Japan. Analysis of inferred allele frequencies hints at a Northeast Asian origin for the Jomon. The authors also show that the genetic contribution of the Jomon is about 33% in mainland Japan and around 60% in the Ryukyu Islands. Additional data, particularly from East Asia, and further analysis will help to refine these estimates, the authors note.
The results supports previous anthropological research suggesting that the Yayoi may have been better equipped than the Jomon to acquire sufficient food to feed a larger population, allowing the rapid expansion of the Yayoi and their subsequent dispersal from western Japan to other regions.