DENMARK: Ancient human genome rebuilt

Scientists have reconstructed the nuclear genome of a man who died in Greenland 4,000 years ago - the first time an ancient genome has been reconstructed in detail - revealing traits including a tendency to baldness, his eye and skin colour and his blood type.

The man was a member of the first culture to settle the Arctic near North America and the researchers used a tuft of his hair to reconstruct the 80% of the nuclear genome that it is possible to retrieve from fossil remains.

The scientists behind the breakthrough say it can be used to find out more about the genetic traits of extinct cultures, identifying the contemporary populations most closely related to extinct cultures, and improving our understanding of heredity and the disease risk passed down from our ancestors.

Professor Eske Willerslev and his PhD student Morten Rasmussen, from the centre of excellence in geogenetics at the Natural History Museum, University of Copenhagen, led the international team of scientists that conducted the research.

They named the subject of their work 'Inuk', which means 'man' or 'human' in Greenlandic, and reported he was more closely related to contemporary north-eastern Siberian tribes than to modern Inuits.

They also revealed that Inuk had a tendency to baldness, dry earwax, brown eyes, dark skin, the blood type A+, shovel-shaped front teeth, and that he was genetically adapted to cold temperatures, and to what extent he was predisposed to certain illnesses.

The findings are significant as the only other human remains of the first people that settled the New World Arctic are four small pieces of bone and hair.

Willerslev's team also revealed that Inuk's ancestors crossed into the New World from north-eastern Siberia between 4,400 and 6,400 years ago in a migration wave that was independent of those of Native Americans and Inuit ancestors.

Willerslev said the latest work was a step up from his previous work on the mammoth genome, which resulted in a sequence filled with gaps and errors due to DNA damage because the technology was in its infancy.

"The genome of Inuk is comparable in quality to that of a modern human," Willerslev said.

"Our findings can be of significant help to archaeologists and others as they seek to determine what happened to people from extinct cultures.

"Doing so requires organic material - bones or hair kept as museum pieces or found at archaeological sites. Previously, the DNA needed to have been frozen or buried in a layer of permafrost. But with the new methods developed here at the Centre, that is not a premise anymore."

The research was conducted with help with scientists in China, where there are more gene sequencing machines than in Denmark, and in the US, UK and Greenland.

The results of the team's research will be published in the journal Nature.