An unprecedented genetic study of more than 150 ancient human remains has turned up new clues about the sudden extinction of Paleo-Eskimos, the earliest-known settlers of the Canadian Arctic.
Above: An Inuit man works on a model kayak with his daughter in Cape Dorset, an Inuit hamlet in the Qikiqtaaluk Region of Nunavat, Canada named after an ancient Paleo-Eskimo culture that went suddenly extinct some 700 years ago. A new study shows today's Inuit are genetically distinct from the Dorset, who may have died out in isolation | Via Library and Archives Canada CC BY 2.0
The results of the investigation – which was led by evolutionary geneticist Eske Willerslev, of the university of Denmark, Copenhagen – are published in the latest issue of Science. Those results support the theory that the Dorset, the last vestige of Paleo-Eskimo culture, disappeared roughly 700 years ago in the span of a few decades. This, after inhabiting the region successfully for some 4,000 years.
Notably, the data also suggest that the Dorset did not form ties with other settlers in the region, as had previously been theorized, but rather perished in isolation. Genetic evidence now indicates that the Dorset assimilated neither with Native American populations, to the south, nor with the Thule. (The Thule people are widely recognized as the ancestors of modern Inuit, who have long been theorized to carry traces of the Dorset in their DNA.)
The study suggests that Paleo-Eskimos arrived in the New World in a single migration, rather than in waves, as previously thought. Analysis of mitochondrial DNA, which allows researchers to pinpoint matrilineal ancestry, suggests rampant inbreeding among the isolated Dorset people, a factor that may have weakened their population and ultimately contributed to their demise.
"Certainly they survived for almost 5,000 years, so they weren't completely destroyed by inbreeding," Dr. Willerslev said. "But it causes a number of medical problems, and I wouldn't be surprised if that had an effect on them."
Another possibility, Dr. Disotell explained, is that the Dorset braved generations of harsh tundra conditions only to succumb to the effects of climate change. In the Arctic, even minor shifts in temperature can devastate marine life, cutting off vital food sources. The archaeological record, in fact, suggests that several such events had nearly wiped out the Paleo-Eskimos before.
"When you're dealing with sea ice, just a few degrees can be transformative," Dr. Disotell said. "Three bad winters in a row where you can't hunt seals, and you're in trouble."
Although the study effectively ruled out the theory that Dorset DNA lives on in the modern Inuit, the mystery of the last Paleo-Eskimos remains unsolved. For Dr. Willerslev and his team, the next step will be to examine even more ancient human remains, in search of clues.
Speculation over climate change aside, the finding that the Dorset did not intermingle with their neighbors is unexpected, if for no other reason than humans really like to do each other. I rather enjoy this quote from Willersev, which he delivered in an interview with National Geographic:
"Elsewhere, as soon as people meet each other, they have sex... Even potentially different species like Neanderthals [and modern humans] had sex, so this finding is extremely surprising."