The ancestors of modern Japanese populations came from three distinct groups who arrived on the island in three different time periods, according to new DNA analysis.
Previous research had identified two groups of ancestors: the hunter-gatherers who lived in Japan 15,000 years ago (and possibly much earlier) and the farmers who migrated to East Asia from ‘around 900 BCE, Harry Baker reports for Live Science. The new discoveries, published in the journal Scientists progress, show that a third group arrived during the Kofun period (around 300 to 700 AD), confirming a theory that some researchers had already mentioned.
“Archaeological evidence has long suggested three stages of migration, but the last one has been largely ignored”, Mikael adolphson, a Cambridge University historian who was not involved in the study, recounts Live Science. “This new finding confirms what many of us knew, but it is good that we are now getting some evidence from the medical field as well.”
Evidence suggests humans lived in Japan 38,000 years ago. Although little is known about these individuals, they may be the ancestors of the hunter-gatherers who created pottery during the Jōmon period, which extends from 13,000 to 300 BCE A second group known as the Yayoi brought agriculture, including rice cultivation in wetlands, to Japan at the end of this period. As ReutersAccording to Will Dunham, modern Japanese have 13 and 16 percent of the genetic ancestors Jōmon and Yayoi, respectively.
The new research sequenced the genomes of the bones of 12 Japanese who lived at different times. The team discovered that a new ancestral source arrived during the Imperial period Kofun period, during the first millennium AD About 71 percent of modern Japanese ancestors came from this third population, Reuters notes.
“Researchers are learning more and more about cultures from the Jōmon, Yayoi, and Kofun periods as more ancient artifacts appear, but prior to our research, we knew relatively little about the genetic origins and impact agricultural transition and subsequent state. training phase ”, explains the main author Shigeki Nakagome, genomic medicine researcher at Trinity College Dublin School of Medicine, in a declaration.
“We now know that ancestors from each of the state’s foraging, farming and training phases made a significant contribution to the training of today’s Japanese populations,” Nakagome adds. “In short, we have a whole new tripartite model of Japanese genomic origin, instead of the long-standing dual-ancestry model.”
The humans who arrived in Japan during the Kofun period were from East Asia and were likely related to the Han, who are the majority ethnic group in China today. The arrival of this new population coincided with the Kofun period, when Japan became an imperial state that led military incursions into Korea and imported aspects of Chinese and Korean cultures. It is not known whether the new migrants contributed to this transformation.
“The sequenced Kofun individuals were not buried in keyhole shaped mounds [reserved for high-ranking individuals], which implies that they were people of lower rank, ”said Nakagome Live Science. “To see if this East Asian ancestry played a key role in the transition, we need to sequence those with higher rank.”
In addition to shedding light on the subsequent migration to Japan, genomic analysis has revealed information about the life of the Jōmon people in a much older era, writes Ian Randall for the Daily mail. Between 20,000 and 15,000 years ago, rising sea levels severed the connection between Japan and the Korean peninsula, separating the Jōmon from other peoples in Asia. Around the same time, the Jōmon began to create a unique style of pottery.
The new study shows that the size of the Jōmon population has remained fairly stable, at just around 1,000 people, for millennia.
“The indigenous Jōmon people had their own lifestyle and culture in Japan for thousands of years before the adoption of rice cultivation during the Yayoi period that followed,” says study co-author. . Niall cooke, a genomics researcher at Trinity, in the release. “Our analysis clearly reveals that this is a genetically distinct population with an unusually high affinity between all individuals sampled, even those that differ by thousands of years and that have been excavated at sites on different islands. These results strongly suggest a prolonged period of isolation from the rest of the continent. “
Unlike much of Europe, where incoming agricultural peoples replaced indigenous hunter-gatherers, Yayoi rice farmers appear to have integrated with the Jōmon, each contributing almost equally to the genetics of later Japanese populations.
“We are very excited about our findings on the tripartite structure of the Japanese populations,” Nakagome told Reuters. “This discovery is important in terms of rewriting the origins of modern Japanese by harnessing the power of ancient genomics.”