The Indigenous people of Canada's Western Arctic are descendants of some of the first humans to live in North America, new genetic research suggests.

A paper published Wednesday in the scientific journal Nature has found the Dene, who live across much of the northern part of the continent and into the southern United States, have roots thousands of years older than previously thought.

"It shows the origin of an entire people," said University of Toronto archeologist Max Friesen, one of the paper's 35 co authors.

For years, scientists have believed North America was populated through waves of migrants from Siberia beginning about 15,000 years ago. Another wave about 5,000 years ago is thought to have brought the Dene. The final one, about 800 years ago, introduced the ancestors of today's Inuit.

Or so went the theory.

The authors examined 48 genomes from ancient and modern people spread across the North from Siberia to Alaska to the Canadian Arctic. What that genetic analysis shows is much more complicated and richer.

The results suggest that the second group did arrive five millennia ago, but it wasn't Dene. Friesen refers to them as Paleo-Inuit.

The researchers believe the first two groups met and mingled, as human groups do.

"Dene peoples, quite clearly, don't represent a separate migration in from northeast Asia," said Friesen.

"Probably in Alaska there was a meeting between Paleo-Inuit and some of those earlier First Nations. They essentially joined together to produce the Dene group, which then expanded into all the areas it is now."

Genetic traces

That expansion was epic.

Dene live in the Mackenzie Valley of the Northwest Territories, the western Yukon, British Columbia, Alberta, Saskatchewan, Manitoba, Alaska and the southwestern United States, where their Athabaskan language links them with the Navajo. In the 2016 Canadian census, 27,430 people identified as having Dene ancestry.

Tulita, N.W.T., near the Mackenzie River. A newly published paper says the Dene who now live along the Mackenzie River have roots thousands of years older than previously thought. (Alex Brockman/CBC)

Even today, genetic traces remain in modern Dene people. Friesen said between five and 23 per cent of their DNA comes from that 5,000-year-old Paleo-Inuit migration.

"The proportion has gradually been decreasing over time because Dene have been interacting with other First Nations," he said.

The origin of Arctic people and their contribution to the settling of North America has been one of the great mysteries in anthropology.

Standard methods such as radiocarbon dating are problematic in the Arctic. The dry, cold climate preserves materials so well that a piece of charcoal from a cooking fire might have come from a tree that was 300 years old when it was burned.

"There's so few archeologists working in the Canadian Arctic," Friesen said. "A tiny, tiny portion of all the relevant sites have even been visited, let alone excavated."