Ancient Siberia sheltered previously unknown humans, scientists say | Science

It was cold, far and involved fighting with woolly mammoths – but it seems that ancient Siberia housed 30,000 years ago a group of robust humans until then unknown. Scientists say this discovery could help solve long-standing mysteries about the ancestors of North Americans.

Native North American ancestors are believed to have arrived from Eurasia via a now-submerged land bridge called Beringia, but it was difficult to determine which groups crossed and gave birth to indigenous populations. ;North America.

Now, scientists say that they may have found answers to the riddles.

In the journal Nature, Eske Willerslev and his colleagues explain how they drew on existing data from modern populations and also analyzed ancient DNA from the remains of 34 individuals from sites in northeastern Siberia, dating from over 31,000 years ago 600 years ago.

The essential remains were fragments of two tiny human milk teeth, shed by men, found in a place in Russia called the Yana Rhinoceros Horn Site. Explored for the first time in 2001, the site offers the first direct evidence of human presence in northeastern Siberia, including bone objects and stone tools. Indirect indices of human populations in northeastern Siberia date back more than 40,000 years.

While previously thought that these remains might be ancestors of North America, the DNA data suggest the opposite.

"What we see here is a much more complex story than we thought we would be," said Willerslev, director of the Geogenetics Center at the Lundbeck Foundation at the University of Copenhagen.

The findings reveal that these individuals were part of a group then unknown and yet still prevalent, dubbed the Siberian Ancients of the North by the genetically distinct team of Eurasians and Asians of the United States. Is. The researchers say that they separated from the old group 38,000 years ago – in other words, shortly after the Eurasians and East Asians got them themselves have become genetically distinct. "They lived like big woolly mammoth hunters and woolly rhinos," Willerslev said.

But, above all, this population does not seem to be the direct ancestor of the Amerindians.

Instead, the analysis of the genome collection suggests that the population that became the ancestors of Native North Americans is the result of connections between approximately 20,000 years ago between East Asians, traveling north, and a group distantly related to the ancient Northern Siberians. East Asians also mingled with other descendants of the former North Siberia to give birth to another group, which the team dubbed the Old Palaeo -Siberian, who then supplanted the existing group.

"[Ancestors of] Native Americans are not the first inhabitants of northeastern Siberia, as most people thought, if it were not everyone, "said Willerslev, adding that the DNA found in north-eastern Siberia from an ancient Paleo-Siberian was crucial for the job. "This is the first evidence that we have, real proof, of something very genetically close to Native Americans," he said.

The team adds that one possibility is that the mix involving East Asians took place in southern Beringia – one of the areas that could have offered respite to difficult living conditions.

The former Paleo-Siberians were themselves supplanted by another east Asian band heading north about 10,000 years ago, giving birth to a group dubbed the "neo-Siberian". "The vast majority of the genetic makeup of today's Siberians comes from this latest effort," Willerslev said. "This is also why you do not have a very close connection between contemporary Siberians and Native Americans."

John Hoffecker, of the University of Colorado, Boulder, who did not participate in the study, welcomed the findings of the research, noting that one of the striking features of this study is that humans are doing well in northeastern Siberia, even under very difficult conditions, 30,000 years ago – with genetic data from the teeth suggesting that men belonged to a population of about 500 people.

"It's a healthy population," he said. "Thirty years ago, we did not know that this robust population of healthy hunter-gatherers was thriving in the high Arctic 30,000 years ago. It's amazing.

Hoffecker added that the group's presence suggests that it is the ice sheets in North America, and not hostile conditions in Beringia, that have prevented people from reaching the Americas earlier.