(CNN) 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.

In a study published in the journal Nature, an international team of evolutionary geneticists revealed the existence of a hardy, mobile group of hunters they termed the Ancient North Siberians. This group was not made up of direct ancestors of Native Americans, as the scientists initially anticipated.

They identified the lost group of people from DNA extracted from two tiny teeth belonging to two unrelated boys, found near the Yana River in Russia.

"These people were a significant part of human history," study leader Eske Willerslev, a professor at the University of Cambridge and director of the University of Copenhagen's Lundbeck Foundation Centre for GeoGenetics, said in a press release.

The researchers estimated that about 40 people lived at the Yana River site where the teeth were found, belonging to a larger population of 500 that hunted bison, woolly mammoths and woolly rhinoceroses. Laurent Excoffier, of the University of Bern, Switzerland, said in a press release that the Ancient North Siberians were "more closely related to Europeans than Asians and seem to have migrated all the way from Western Eurasia soon after the divergence between Europeans and Asians."

The scientists also found a fragment of a "decorative ivory hair ornament or head band" at the Yana site.

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