Science has long established that people living in what is now Siberia once crossed the Bering Strait into North America on foot (and later by rowboat). But new evidence shows that these early migrations were not one-way trips: In a study published in the journal Current BiologySome researchers say they have discovered traces of Native American ancestry in the DNA of Siberians who lived centuries ago.
This Native American heritage, which is still present in the genomes of some Siberians today, adds to a body of archaeological evidence indicating that North Americans were in contact with their neighbors in northern Asia for thousands of years before the arrival of Europeans.
The discovery is not entirely unexpected. “Human movement is rarely unidirectional,” says Cosimo Post, co-author of the new study, an archaeologist at the University of Tübingen in Germany. “There’s usually a little back and forth.”
How and when humans first arrived in the Americas is one of the longstanding debates in the field of archaeology. Presumed dates vary widely, but many researchers agree that the first immigrants may have crossed the Bering Bridge, a strip of land periodically connecting northern Asia with present-day Alaska in prehistoric times. This transcontinental highway succumbed to sea level rise between 11,000 and 10,000 years ago, but this has not stopped migration between the two countries. Genetic studies and archaeological excavations indicate that the peoples of Siberia moved to North America many more times, even 1,000 years ago.
But while much research has focused on reconstructing how people got to what is now Alaska, “very little is known about migration the other way,” Post says.
This situation is slowly starting to change. Study 2019 She found genetic evidence that ancient people living on both sides of the Bering Strait were in contact with each other. And a few Alaskan archaeological finds – including Discovery of glass beads from the fifteenth century which may be of Venetian origin – indicating continued trade between North America and the rest of the world.
What is not clear is how far these relations extend beyond the strait. Little is known about how people moved within Siberia over the past thousand years. Hoping to reconstruct this part of the region’s history, Post and his colleagues sequenced the DNA of 10 ancient peoples whose remains were discovered at various sites in Siberia.
The oldest such specimens date back 7,500 years. The study also included the genomes of three people who lived just 500 years ago on the Kamchatka Peninsula, which stretches from far eastern Russia to the southwest of the Bering Strait. According to Posth, these sequences are the first samples of ancient DNA from the remote peninsula.
Researchers have discovered that Siberia was once a center of migration, connecting ancient Siberians with people as far away as Japan and Greenland. Their analysis also revealed a hitherto unknown connection between the Native Americans and the people who lived in Kamchatka a few centuries ago. The team found that the ancestors of the Kamchatkas had already met North Americans at least twice: once between 5,500 and 4,400 years ago and again about 1,500 years ago. These links show the influence of Native Americans in regions much further inland than previous studies.
Posth says he was expecting to find some evidence of Native American contact in Siberia, but he was surprised at how early these encounters occurred. These contacts were not the last time Kamchatkas interacted with North America. The team found a higher proportion of Native American DNA in the genomes of modern Kamchatka residents, indicating that the people of the peninsula also had contact with North America in recent centuries.
According to Posth, it remains unclear how North American DNA got into the genomes of Kamchatka residents. Their ancestors may have inherited DNA from other Siberians with this gene, or they may have been in contact with Native Americans. However, the study by Posth and colleagues builds on previous genetic research to show that DNA traveled from North America to Siberia, says University of Kansas genetic anthropologist Dennis O’Rourke, who was not involved in the new post.
The fact that the peoples of North Asia and North America came into contact is not surprising, given how close the two lands are, says Anne Stone, an expert in genetic anthropology at Arizona State University, nor is she involved with the new research. On the one hand, the Aleutian Islands (where the Aleut people historically hunted and traded) form a range that starts off southwestern Alaska and extends westward just to Kamchatka.
As for the Bering Strait, Stone argues that while the first inhabitants of the area may have been isolated from one another after the disappearance of the Bering Bridge, later generations were not so constrained. “They had boats,” Stone concludes. Then they can visit each other and exchange trade with them.
(The original of this article was Published in Scientific American on January 12, 2023. Translation and editing by Le Scienze. Reproduction is authorized, all rights reserved.)
