A 10,000-year-old male remains found in a site in Siberia represented the base of this discovery, and the analyze of his DNA shows us that his ancestry comes from a mixture of Ancient North Siberian DNA and East Asian DNA, being very similar to that found in Native Americans.
For the new study, published this week in the journal Nature Communications, researchers analyzed DNA samples from 34 individuals recovered from Russia's Yana Rhinoceros Horn Site, an archaeological site in northeastern Siberia.
Two 31,000-year-old milk teeth have led to the discovery of an ancient group of people who once lived in northern Siberia - and, along with a 10,000-year-old skull, could offer a better understanding of who the ancestors of Native Americans were, scientists say.
Lead author of scientific work, Professor Eske Willerslev, said these people had to adapt to very harsh conditions.
Dr Martin Sikora, of The Lundbeck Foundation Centre for GeoGenetics and first author of the study, added: "They adapted to extreme environments very quickly, and were highly mobile".
'These findings have changed a lot of what we thought we knew about the population history of north eastern Siberia, but also what we know about the history of human migration as a whole'.
According the the scientists, Yana was likely home to around 40 individuals, while the larger population in the area was probably closer to around 500 people. Genetic analysis of the milk teeth revealed the two individuals sequenced showed no evidence of inbreeding which was occurring in the declining Neanderthal populations at the time.
The study, in which 34 samples of human genomes from the archeological sites across northern Siberia and central Russian Federation were analyzed, reveals that the Ancient North Siberians are more related to Europeans than Asians, being possible ancestors of the contemporary people from northern Eurasia and America.
In research, it is generally accepted that humans came to America for the first time by crossing the Bering Strait from Siberia to Alaska, using a land bridge that existed before the last ice age ended. These early peoples eventually became indigenous Americans, including Alaska Natives, Canadian First Nations, and Native Americans.
During the Ice age in Siberia, lived previously unknown to scientists a group of hunters who are "specialized" for the big game: woolly mammoths, wolves and bison.
The DNA analysis from the milk teeth revealed they belong to the only human remains found in the site that belonged to that era.
While it had previously been thought that these remains might be from the ancestors of native North Americans, the DNA data suggests otherwise. About two-thirds of her genome bears a remarkable similarity to those of living Native Americans, making her "the closest we have ever gotten to a Native American ancestor outside the Americas", Willerslev told Michael Price at Science.
Crucially, this population is not a direct ancestor of the Native Americans, being genetically distinct to them.
While it is commonly believed the ancestors of native North Americans arrived from Eurasia via a now submerged land bridge called Beringia, exactly which groups crossed and gave rise to native North American populations has been hard to unpick.