For at least the last century archaeologists and anthropologists have generally agreed that the first humans arrived in North America having struggled across the icy wastes of Beringia, a vast land mass that bridged the seas between Siberia and Alaska. However, this has always been a ‘good theory’ because nobody was quite sure of the exact origins of these first peoples. Did the first arrivers survive as an unbroken lineage for over 15,000 years, leading to today’s Native Americans , or not, is the question?

Beringia formed about 34,000 years ago and the first humans hunted their way across it more than 15,000 years ago with major migrations of Paleo-Eskimos about 5,000 years who populated the American Arctic region and southern Greenland. However, it has been a thing of debate; if today’s Eskimo-Aleut and Na-Dene speaking peoples are ‘direct ancestors’ of these ancient wanderers, or are related to later migrations of what are known as Thule people (Neo-Eskimos), about 800 years ago.

Different groups have mixed and migrated throughout Siberia in Russia and into North America over the past 40,000 years. Image: Martin Sikora/ Nature

The Two Pronged Genetic Approach Always Wins!

The pair of new DNA studies were built around data correlated from “rare fossils on both sides of the Bering Strait ”, which according to Smithsonian Magazine , “help write new chapters in the stories of these prehistoric peoples.” Published in Nature.com, the international team in the first of the two new studies analyzed the “genetic structures of modern and past Paleo-Eskimos and their descendants, who were among the earliest people in North America .”

The team, led by co-author David Reich of Harvard Medical School, compared the genes of “93 living Alaskan Iñupiat and West Siberian peoples remains of 48 ancient humans from the region”, and according to the paper, this confirms that “Yup’ik , Inuit, Aleuts and Na-Dene language speakers from Alaska and Northern Canada inherited some of their genes from Paleo-Eskimos.”

Two Sides Of The Same Genetic Problem

While the first study concentrated on North American genes the second focused on Asian genetic lineages. Also published in Nature, this project had its research team retrieving “genetic samples from the remains of 34 individuals in Siberia, dated between “600 to 31,600 years old.” In this study, a discovery that stood out was made in the DNA of a Siberian individual who died about 10,000 years ago. It contained what the paper says is a “genetic resemblance to Native Americans, more so than any other remains found outside of the Americas.”

The archaeological site where two 31,000-year-old milk teeth were found. (Image: Elena Pavlova )

Led by David Meltzer, an anthropologist at Southern Methodist University, who coauthored the new study, the researchers in this second paper suggest that during the about 26,500 to 19,000 years ago, during the ‘Last Glacial Maximum’ changing environmental conditions forced about “500 or so Ancient North Siberians” to travel from southern Beringia with folk migrating from East Asia. This mixed nomadic population would give rise to both the lineages that dispersed through Siberia and the first Peoples of North America.

Meltzer wrote, “It doesn’t change the fact that there’s no direct historical descent in terms of the artifacts, but it does tell us that there was this population floating around in far northern Russia 31,000 years ago whose descendants contributed a bit of DNA to Native Americans.”

The two 31,000-year-old milk teeth found at the Yana Rhinoceros Horn Site in Russia which led to the discovery of a new group of ancient Siberians. Credit: Russian Academy of Sciences / Nature

Ancient Chickens And Eggs

When these two studies are brought together they confirm what has always been suspected, but they also highlight that ancient people migrated both east and west. This became apparent when the scientists tested a relatively modern genome, about 10,000-years-old, that was unearthed near Siberia’s Kolyma River. The DNA was found to be mixture of Ancient North Siberian lineages and East Asian “and similar to that seen in Native American populations - a much closer match than any others found outside of North America.”

Meltzer says, “The Bering land straight… Was open, relatively flat, no glaciers - it wasn’t like you wander through and the door closes behind you and you’re trapped in America” so people flowed in both directions during the Pleistocene.

The studies both published by Nature and are available at the following DOIs:

https://doi.org/10.1038/s41586-019-1251-y

https://doi.org/10.1038/s41586-019-1279-z

Top image: Two men found at the Yana Rhinoceros Horn Site in northern Siberia in Russia date to about 32,000 years ago, providing the earliest direct evidence of humans in the region. Source: Elena Pavlova

By Ashley Cowie