"Inuk" is the first Ancient Human whose biological history is reconstructed from complete DNA analysis. He was a brown-skinned, brown-eyed man with shovel shaped teeth and blood group A positive. His metabolism was genetically well equipped to survive the Arctic environment. His hair grew thick but was probably balding.
The swatch of hair had been preserved in permafrost for 4000 years, then unearthed by archaeologists at Qeqertasussuk on Disko Bay, Greenland. The hair was among items of rubbish discarded by the extinct Saqqaq culture. Since analysis suggests that the sample was from a younger person, it may have been discarded after a haircut.
It used to be thought that DNA would be found only in cells at the roots of hair, not in the keratin that forms the hair shaft. It is now known that the cells become incorporated into the growing shaft and their DNA is sealed in by the keratin, protecting it from attack by bacteria and fungi.
DNA in Personal Genomics
Developments in DNA sequencing technologies have instigated an epoch of personal genomics - the analysis of individual DNA to illuminate histories of populations. Eight human genomes have been reported so far. Genomes have been sequenced for individuals with ancestry in three distinct geographical regions, Africa, China and Europe:
- one Yoruba African
- four Europeans
- one Han Chinese
- two Koreans
Analyses of DNA fragments of genomes have so proliferated that various traits can be diagnosed through comparisons between other samples. This is how Inuk's physical characteristics can be reliably understood, and how his analysis will enable evolutionary comparisons to be developed.
Seeking Evolutionary Perspectives
Eske Willerslev, Professor for Ancient DNA and Evolution at the University of Copenhagen, is convinced that, to gain an evolutionary perspective, it is necessary to uncover past human genetic diversity and composition. Modern genomics has been restricted by not being able to trace this connection, the only Ancient Human samples previously analysed being incomplete, from a Neanderthal.
Excavations of neolithic settlements in the New World Arctic have occurred periodically since the 1950s and revealed large amounts of information interpreted from the extensive finds and sites as the Arctic Small Tool tradition. An ethnography for the so-called 'Saqqaq culture' is devised from comparing Greenland sites, and comparing their cultural remains against ethnographies of groups still in existence. Although many artefacts from the AST tradition have been found, few human remains have been recovered.
In 2006 Willerslev joined an expedition to Peary Land, North Greenland specifically to collect human remains for DNA analyses. No suitable remains were found. On mentioning his disappointment to a colleague, Willerslev was pointed towards the basement of the National Museum of Denmark where quantities of Saqqaq artefacts collected in 1986 were stored, unfrozen, in plastic bags, including tufts of hair.
Genetics Crosslinked with Ethnographies
The large group of scientists in various institutions across the world collaborating on the project reported in Nature matched their findings with analyses of other evidence about the Saqqaq people. In addition, they compared Inuk's results against various indicators in samples from modern populations around the Arctic. For comparison, genotyping on four native North American and twelve north Asian populations was performed.
Results show that this individual has genetic commonalities with three Old World Arctic populations:
- Nganasans
- Koryaks
- Chukchis
and is more distantly related to three New World groups:
- Amerinds
- Na-Dene
- Greenland Inuit.
The Nganasans inhabit the Taimyr Peninsula, some 2,000km from the Bering Strait and are the northernmost living Old World population. Koryaks and Chukchis inhabit Chukotka and northern Kamchatka in far eastern Siberian. The mtDNA genome also demostrated Saqqaq as related to Aleuts of Commander Islands in the Bering Sea, and Asian Eskimos the Siberian Sireniki Yuits.
Genome Analysis as Forensic Method
Saqqaq reliance on marine food, especially harp and ringed seal, was revealed by light isotope analyses of carbon and nitrogen in the hair. Accelerator mass spectrometry radiocarbon dating produced a date of c2000 BC and morphological analysis using light and scanning electron microscopes revealed excellent overall preservation.
Information garnered from this genome analysis is so complete that it is possible to tell that this Saqqaq is likely the product of two first cousins, to reconstruct his probable appearance and susceptibility to disease, and that he would have had the dry kind of ear wax known among Asians and Native Americans.
Together with the information already collated through SILA, the Greenland Research Centre at National Museum of Denmark, this genomic evidence is now contributing to further ethnographic and demographic interpretation of the origins of human habitation of the Arctic region. For instance, it points towards a previously unknown migration from Siberia into North America 5500 years ago.
With a full genome analysis well underway for Neanderthals and Wellerslev's interest in South American mummies and Homo heidelbergensis (pre-Neanderthal), the prospects for genomics in forensic anthropology appear exciting.
Sources
- Professor Eske Willerslev Ancient genomes: The Saqqaq Genome Project University of Copenhagen
- Rasmussen et al (2010) 'Ancient Human Genome Sequence of an Extinct Palaeo-Eskimo' Nature 463 February 10 pp. 757-762
Valerie Williamson - Dr. Val Williamson is a freelance journalist and academic specialising in historical and popular culture topics.
