Ancient DNA Blueprints: Native American Journeys to Asia Thousands of Years Ago | Sciences

Whether by walking a land bridge or traveling by boat, hunter-gatherers ventured out of eastern Eurasia 20,000 to 30,000 years ago To become the first Americans. But the transcontinental trip was not a one-way trip. Genetic studies show several times in history that Native Americans moved back across the Bering Strait into Eurasia—long before Europeans began arriving in remote parts of the Americas.

Now, new genetic research is mapping those ancient migrations back and forth across the Bering Strait and elsewhere across Eurasia during key periods of human prehistory. Scientists recently recovered ancient DNA from the well-preserved bones and teeth of 10 individuals from eastern Eurasia, from 7,500 to 500 years old, who are published Their findings on Thursday in Current Biology. The new evidence helps show that from the coasts of America and Japan to the interior regions of Siberia, some of the populations of our deep ancestors may have been more mobile and mixed than anyone had imagined.

Cosimo Post, an archaeologist at the University of Tübingen in Germany, and his colleagues described the genomes of ten different individuals who lived in three main regions: Siberia’s Altai Mountains, the Kamchatka Peninsula and other parts of the Russian Far East. The environmental conditions – cold climates at high latitudes – allowed for optimal preservation of DNA that was hundreds to thousands of years old. “In these environments, you can find individuals who have 70 to 80 percent of human DNA in their bones, which is comparable to what you would get if you extracted saliva from you or me,” Posth says. You can actually create a genome as good as a modern genome. It’s great stuff.”

Analysis of the DNA of these 10 individuals has provided several key discoveries about ancient migrations. First, the vast movements of ancient humans and cultures across Eurasia is evidenced by the discovery of an entirely new population that lived in the Altai Mountains of Siberia. The authors show that the descendants of that culture were part of the lineages that later helped populate both Europe and the Americas. Second, people of the Japanese Jōmon culture, isolated in the archipelago for thousands of years, migrated to the Asian mainland from which their ancestors came. Finally, Native Americans migrated to Asia several times over the millennia.

The remains of some of the older individuals studied, dating to about 7,500 years before the present, are part of a previously unknown population of hunter-gatherers that lived in the Altai Mountains. Today this crossroads is a kind of Eurasian four corners where Russia, Mongolia, China and Kazakhstan are united with each other. Going back to the early Holocene, at least 10,000 years ago, the people of Altai lived in an area that was slowly warming. Posth’s analysis shows that this group was a genetic mixture of two distinct groups that lived in different parts of Siberia during the last ice age: the Paleo-Siberians and the Ancient Eurasians. Population of Paleo-Siberia Contributed to the entry of the first wave of people to the AmericasAnd many Native Americans today can trace parts of their ancestry to this group. The ancient North Eurasian lineage first appeared in a 24,000-year-old Mal’ta individual from the Lake Baikal region, and over time became an important genetic Contributions for almost the entire population of Europeand to later North American migrations as well.

Altai Mountains in Siberia is the same region in which it is found A fragmented finger bone was discovered in 2010 It turned out, after analyzing the DNA, to identify a completely new type of human relative – Denisovans. Their lineage, which existed from about 400,000 to about 30,000 years ago, turns out to be Bit complicated One. In 2018, scientists learned that a 13-year-old girl, found in a mountain cave, was born in Denisovan mother and Neanderthal fatherwhich indicates that different species not only cross paths in the area but also reproduce.

“This also appears to be an important area for us, for humans,” says Posth. “This could be a corridor and crossroads where residents can mix.”

Posth was surprised by the scale of human migrations revealed by the diverse DNA. “I was expecting movement perhaps from one valley to another, but here we are talking about movement and mobility on a large scale among these groups across vast regions of North Asia.” According to co-author Ke Wang, of China’s Fudan University, one individual was found in Nizhnetytkesken Cave with burial goods such as stone points, ornaments, and animal claws that may indicate religious overtones and a possible practice of shamanism. The genetic profile of this 6,500-year-old individual was different from its contemporaries in the Altai region and more similar to populations from the Russian Far East, suggesting that it could have come from a genetically and culturally distant region.

These types of mixed migrations gave rise to the unique population of Altai, and similar events can be traced in the genes of its descendants as well. For example, genetic evidence suggests that an Altai hunter-gatherer society may be the source of an ancient North Eurasian ancestry discovered in groups such as Mummies of the Tarim Basin Bronze Age cultures Lake Baikal region Southern Russia.

The study also revealed links between the remains of 7,000-year-old individuals from the Russian Far East and the islands of Japan. The remains had large amounts of lineage associated with the Jomon, a group of hunter-gatherers from the Japanese archipelago

Genomic analysis is suggested that Jomon, Unique pottery makersThey lived in relative isolation from 20,000 to 15,000 years ago until nearly 3,000 years ago, when traditional fishermen mingled with a new influx of rice farmers on the islands. But the new study reveals that some Jomon left the islands for the mainland before that mixing, and crossed the sea 7,000 years ago.

The results also reveal the ancient comings and goings across the Bering Strait. Scientists have already stated that groups in Asia made at least three major migrations to the Americas – approximately 20,000, 5,000 and 1,000 years ago. But those events are only half of the story. Mounting genetic and archaeological evidence reveals that some populations made the round trip. The new study identifies the timing of some of the back migrations, and shows that they were extensive enough that Native American lineages extended far from the coast, reaching the Kamchatka Peninsula and central Siberia.

Posth and his colleagues compared the genomes of three 500-year-old individuals on the Kamchatka Peninsula with people who live there today. “Individuals 500 years old have significant amounts of Native American ancestry,” he says, “but those living on the same peninsula today have twice as many.”

This finding means that some Native Americans may have returned to Eurasia 500 years ago, possibly about 5,000 years ago, according to estimates of the time of genetic convergence in ancient samples. It also revealed that Native American peoples migrated across the Bering Strait recently. Scientists cannot definitively say where those migrations originated from; Each of the Native American populations the group tested—the ancient Aleut, Athabaskan, and ancient Bering Sea lineages—could have served as an alternative source of genetic input.

Finding genetic evidence for Native Americans in Eurasia isn’t surprising, notes David Meltzer, an anthropologist at Southern Methodist University who was not involved in the study. When Beringia [the land bridge] It sank nearly 12,000 years ago, which only means that it is no longer possible to walk from Northeast Asia to America. About 6,000 years ago, perhaps a little earlier, groups using watercraft easily crossed the Bering Sea.

former Genetic evidence found Both in ancient remains and among the contemporary Chukchi peoples of Siberia it has already been suggested that humans moved in both directions across the Bering Sea thousands of years ago. “What this new paper does is it gives us a better idea of ​​the likely number and timing of return migration episodes,” says Meltzer.