All that is left of him are four tufts of hair and four fragments of bone, yet the DNA of an Eskimo who died 4,000 years ago in Greenland has shed new light on human history.
Inuk — named after the word for man in the Greenland Inuit language — is the first ancient human being to have his genetic code read, offering important insights into his biology, appearance and migrations.
DNA extracted from Inuk’s hair has revealed that he had dark skin, brown eyes and shovel-shaped front teeth — and that his ear wax had a dry consistency, making him more vulnerable to infection. His thick black locks may have been thinning: his genes suggest a predisposition to baldness.
The results also highlight an ancient migration previously unknown. Inuk’s DNA shows that he was more closely related to the Koryak and Chukchi Eskimo tribes of modern Siberia than to the Inuit of Canada and Greenland.
This indicates that his people crossed the Bering Strait to North America independently of the indigenous groups that still live there today.
Inuk’s genome, which is published in the journal Nature, is by far the oldest human genetic code yet read — all those completed previously used tissue taken from living people.
The achievement, by a team led by Eske Willerslev and Morten Rasmussen, of the University of Copenhagen, demonstrates a powerful new tool. It opens the way for other groups to use DNA from human remains to investigate past migrations and the ancestry of populations now extinct.
Professor Willerslev said that such sequencing could be used to study Native American peoples wiped out after the European conquest of the New World, and Tasmanian Aborigines, the last of whom died in 1876.
Inuk’s remains were discovered 25 years ago, preserved in permafrost at Qegertasussuk in Greenland. They were identified as belonging to an individual from the Saqqaq culture, a Stone Age civilisation living 4,750 to 2,500 years ago. In 2003 Professor Willerslev applied to the National Museum of Denmark to use a bone sample for sequencing but was refused permission because the sample would be destroyed. Later, a colleague told him that hair had been taken from Inuk as well.
It was “in a drawer in a plastic bag, without people paying much attention to it”, he said. He was given permission to extract DNA. As the hair had been preserved in permafrost it was largely uncontaminated.
Analysis revealed that Inuk had a tendency to baldness “and because we found quite a lot of hair from this guy we presume he died quite young”, Professor Willerslev said.
Inuk was genetically adapted to cold temperatures even though it was not many generations since his people moved to the Arctic. His genetic similarities to the Chukchis and Koryaks of eastern Siberia suggest that the Saqqaq were descended from a group that migrated from Siberia to North America 5,500 years ago, several thousand years after the ancestors of the Inuit and Native Americans crossed the Bering Strait.
As there was no land bridge between Siberia and Alaska at the time, the Saqqaq’s ancestors must have crossed by boat or over ice, he said. But there was “no clear answer” about why they settled in the Arctic rather than more temperate regions.Isotope analysis suggests that Inuk followed a diet rich in sea creatures such as seals and sea birds.
In a Nature commentary, David Lambert and Leon Huynen, of Griffith University, in Queensland, Australia, said the work opened exciting possibilities for genetic archaeology. But they warned that useable DNA could be harder to extract from remains not preserved in permafrost and that most ancient human remains are found in temperate or hot environments.
Source: Times Online