Remember how excited you were when you saw Jurassic Park and considered the possibility of recreating an extinct species from a fragment of DNA? Of course the small issue of translating this genetic code into a fully functional living creature, without sexual reproduction, was of course only considered later. Nevertheless, all is not lost.
This month, in the prestigious science research journal Nature, a team of evolutionary biologists, led by the Dane Eske Willerslev, have become the first to sequence an entire ancient human genome. This exciting work has overcome the difficulties associated with obtaining high quality, uncontaminated ancient DNA thus allowing the team to present us with a detailed picture of what an ancient human may have looked like. As an added bonus the work also solves a long running debate amongst evolutionary biologists and ethnologists regarding migration patterns into the New World. The original sample used to obtain the DNA came from an excavation in Greenland in 1983 which recovered a small tuft of hair from a 4,000 year old Paleo-Eskimo of the Greenland-based Saqqaq culture. The sample had been sitting idly in the basement of the Natural History Museum of Denmark for twenty years, just waiting for Willerslev and his team of DNA sequencers.
Aside from the excitement of being the first to completely sequence an ancient human being, Willerslev’s work also gives us a snapshot into who this man was and how he may have appeared. By sequencing 80% of the three billion base pairs of DNA twenty times over, a standard twice as rigorous as that applied to the Human Genome Project, Willerslev not only cracked the ancient human code, he was able to determine uniquely personal facets of this ancient human’s physical makeup. The original owner of the hair and the DNA, now affectionately named Inuk, was most likely a dark skinned, dark haired man with A+ blood, a propensity for baldness, and teeth that morphologically resemble those of people of Asian or Native American descent. No doubt, as we begin to understand more about our own DNA and the function of the genes it codes for, we will be able to go back to Inuk’s DNA for comparison, and infer even more physical characteristics. It may even be possible to one day determine characteristics of his personality and his lifestyle.
Even more exciting for evolutionary biologists was that Inuk’s DNA sequence was able to solve a long running debate regarding the migration of the Saqqaq people into Greenland. By comparing the Inuk’s DNA to the DNA of various ethnic and cultural groups geographically related to Greenland, Willerslev’s work shows that the Saqqaq are not the ancient descendants of modern Inuit groups, nor were they descended from native Americans who might have migrated into Greenland. Instead the Saqqaq are most closely related to the Chukchis people of Siberia. The genetic divergence between the two groups probably occurred just prior to the Saqqaq migration that would have seen them travel across the Bering Strait and across Alaska and Canada to Greenland.
Whilst the conclusions regarding the migration patterns of the Saqqaq people no doubt solves an ancient riddle, for many of us the most impressive feature of this discovery lies in the sequencing method and the possible future applications and implications of this technology. Willerslev hopes to apply his methods to other human remains around the planet but admits that it will be difficult to extract good quality uncontaminated DNA from samples that have not been preserved by permafrost. Nevertheless, there is a real hope that more mysteries will be solved about where we came from and who we were. And just maybe, somewhere down the track, there may even be room for a Jurassic pet dinosaur.
