The Ainu people indigenous to the northernmost main Japanese island of Hokkaido share more genes with people in the nation’s southernmost Okinawa island chain than with the people of the nation’s main islands, according to a Japanese study.
Researchers at Graduate University for Advanced Studies (GUAS) analyzed DNA in blood taken from 36 Ainu in the town of Biratori, Hokkaido and those from 35 Okinawans. They compared 600,000 genome locations to note individual genetic differences between the subjects in each group and against pre-existing DNA data for 243 mainland Japanese. The analysis revealed that Ainu are closer to Okinawans than to mainland Japanese. Mainland Japanese were found to be genetically closer to Okinawans and to Koreans than to Ainu.
Modern Japanese represent a mixing of people who had lived in Japan from the Jomon period (roughly 14,000 BC to 300 BC) with a wave of immigrants from mainland Asia who arrived in the Yayoi period (300 BC to AC 300).
The new study suggests newcomers mixed mostly with those in the three main southern islands of the Japanese archipelago and far less with those living in Hokkaido and the Ryukyu Islands which make up today’s Okinawa Prefecture, said GUAS professor Naruya Saito who led the study.
The Ainu have long been perceived as having a different origin than the majority of Japanese. They are shorter, stockier, lighter-skinned, more hairy and have larger noses than typical Japanese, prompting early speculation that they may even be a Caucasian subgroup. More recently, however, they have been linked genetically to southeast Asians.
Similarities between them and Okinawans were first noted in 1911 by a visiting German pathologist. The recent GUAS study provides genetic evidence to back up those observations.
“Going forward, we’d like to analyze the DNA in the bones and teeth of Jomon period individuals to better clarify the genetic origins of modern mainland Japanese,” Saito told Mainichi Shimbun.
The GUAS study was published Thursday in the English version of the online journal of the Japan Society of Human Genetics.