The harsh, frigid New World Arctic was the last part of the Americas to be populated by modern humans. But who the first Eskimos were and when they arrived have been hotly debated by scientists. In an unprecedented genetic analysis, researchers say the frosty region was peopled in distinct waves of migration; the first to arrive keeping to themselves for thousands of years until mysteriously vanishing 700 years ago. The findings were published in Science this week.
Based on tools and other artifacts, archaeologists believe the first inhabitants of the North American Arctic—Alaska, Canada, and also Greenland—arrived 6,000 years ago after crossing the Bering Strait from Siberia. The Paleo-Eskimos showed up first, with the Neo-Eskimos appearing almost 4,000 years later. The Paleo-Eskimos exhibited a variety of distinct cultures, Science explains: The Saqqaqs lived in tent camps and chased caribou and seals. Succeeding them were walrus hunters called the Dorsets and finally came the Thules, whale hunters who sailed in large skin boats.
To see how all these different cultures are related, a huge international team led by Eske Willerslev from the University of Copenhagen collected preserved bone, teeth, and hair samples of 169 ancient humans from Arctic Siberia, Alaska, Canada, and Greenland, and then analyzed their mitochondrial DNA. (Pictured to the right, a researcher looking for ancient human remains in northern Greenland.) The team also sequenced the genomes of seven people living in the region now.
Their analyses reveal that the arrival of Paleo-Eskimos into North America was separate from the later pulse of migration that gave rise to today’s Inuits and Native Americans further south.
“The Paleo-Eskimos—representing one single group—were the first people in the Arctic,” Willerslev says in a news release. “After surviving in near-isolation in the harsh Arctic environment for more than 4,000 years," adds Maanasa Ragahavan from the University of Copenhagen, "[they] disappeared around 700 years ago—about the same time when the ancestors of modern-day Inuit spread eastward from Alaska."
Previously, researchers were unclear on whether different populations of Paleo-Eskimos (the Saqqaq and the three Dorset cultures) had the same ancestral population. The new study reveals that all Paleo-Eskimo cultures shared a common Siberian ancestor, but their genetic continuity was interrupted by the arrival of a new population: the Neo-Eskimo Thule people, ancestors of modern-day Inuits.
The team found evidence for gene flow between Paleo-Eskimos and the Thules, but it likely occurred back in Siberia—and not in the Arctic, where the groups were largely separated.
“When we see people meeting each other, they may fight each other, but normally they also have sex with each other,” Willerslev tells Science. “That does not seem to be the case here.” Researchers aren’t sure why the Paleo-Eskimo lineage disappeared after the late Dorsets: Perhaps they were pushed out to the fringes or annihilated by a disease. He adds: "It's just mind-blowing to imagine an entire people who just completely vanished.”
Images: Carsten Egevang (top), Claus Andreasen (middle), M. Raghavan et al., 2014 (bottom)