A team of researchers led by Maanasa Raghavan from the University of Copenhagen have reported in Nature on their sequencing of the oldest modern human genome to date. The sample comes from a 4-year old boy who was buried at the site of Mal’ta in south-central Siberia. It concerns an Upper Palaeolithic burial, ca. 24,000 years old.
The genome from this skeleton gave a dual signal. Parts of it relate to western Eurasians, while other parts are uniquely found in Native Americans. Interestingly, this genome shows no affinities with Eastern Asia, while today’s Native Americans are most closely related to East Asians. These results have two main implications. Firstly, it illustrates how western Eurasians had a more north-easterly distribution 24,000 years ago than commonly assumed, entering America by crossing from Siberia. Secondly, the role of these First Americans into the genetic composition of the current Native Americans is more pronounced than previously expected. The authors estimate that 14 to 38% of Native American ancestry may relate back to gene flow from this ancient population.
Further support to these findings is giving by:
– the related archaeology: The boy was found in association with a venus figurine, a common object in the European Upper Palaeolithic.
– Other DNA sequencing: another south-central Siberian, Afontova Gora-2 dating to approximately 17,000 years ago gave a similar genetic signal.
– Palaeoanthropological remains: some skulls from the First Americans (e.g. 9,000 year old Kennewick Man) have been described in the past as bearing morphological characteristics typical of Europeans and different of East Asians
So this study indicates that Native Americans reflect the meeting of two populations – an East Asian one and these Mal’ta west Eurasian populations. Where and when actually this meeting took place is still unknown and further sequencing of early skeletons from the Americas should help shed further light on the nature of Native American origins.
Reference: Raghavan, M. et al. 2013. Upper Palaeolithic Siberian genome reveals dual ancestry of Native Americans. Nature. doi:10.1038/nature12736