Copenhagen scientists map genes of extinct human

Scientists can now reconstruct the genes of an ancient human being.

Using a tuft of hair, Copenhagen scientists have sequenced the genome of a 4000-year old Greenlander, giving insight into the traits of ancient peoples, heredity, and the peopling of the Arctic region.

The findings, which are described in detail in the science journal Nature, are by Professor Eske Willerslev and PhD student Morten Rasmussen, from the Centre of Excellence in GeoGenetics at the Natural History Museum, University of Copenhagen, together with an international team of scientists.

Named ’Inuk’

The hair was found during an excavation in north-western Greenland in the 1980’s and now stored at the National Museum in Denmark.

»After the Greenland National Museum and Archives granted permission, we analysed the hair for DNA using various techniques and found it to be from a human male. […] we finally managed to sequence the first complete genome of an extinct human,« Willerslev says.

The scientists have already named the ancient human ‘Inuk’, which means ‘man’ or ‘human’ in Greenlandic. Inuk is more closely related to contemporary north-eastern Siberian tribes than to modern Inuits of the present day New World Arctic, but the scientists wants to acknowledge that the discovery was made in Greenland.

Independent of other migrations

The same technique can be applied to other ancient remains, the scientists say, allowing the reconstruction of the human traits of extinct cultures. It will also shed light on ancient human expansions and migrations, heredity, and the disease risk passed down from our ancestors.

The genetic sequence is actually only the maximum 80% of the genome that is possible to retrieve from fossil remains, but it can give a description of how the pre-historic Greenlander Inuk looked – all the way down to details such as his baldness, dry earwax, brown eyes, dark skin, his blood type A+, and his shovel-shaped front teeth, and his genetic adaptation to cold temperatures, they say.

Eske Willerslev’s team show that Inuk’s ancestors crossed into the Americas 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. Inuk and his people left no descendants among contemporary indigenous people of the New World.

Morten Rasmussen explains to the University Post that this could be because Inuk’s group for unknown reasons went extinct with no genetic descendants, or because the group migrated elsewhere.

Fast sequencing

Inuk’s genome is comparable in quality to that of what can be achieved for a modern human.

The actual sequencing work was carried out with other scientists at the University of Copenhagen and in China, where they have far more sequencing machines than in Denmark.

»Reconstructing an entire modern human genome used to take years. But the new methods and the abundance of sequencing machines allow us to do it in just a few months – and that includes the time-consuming task of analysing the results,« Morten Rasmussen says.

Not Frankenstein

He hastens to add however, that the genome does not allow science to physically reconstruct an actual Inuk like a modern-day Frankenstein.

»It’s more like we’ve got the blueprints for a house, but we don’t know how to build it. It is impossible at present to actually reconstruct a human being from the sequence, but this is not to say that it is not possible some time in the future,« he says.

miy@adm.ku.dk