Ancient North Eurasians from Siberia

September 3, 2020

Ancient North Eurasian (ANE) is a genetic component that traveled mainly east into Native Americans, but also west into Europeans. It's represented by pre-historic individuals discovered in Siberia:

Here we sequence the draft genome of an approximately 24,000-year-old individual (MA-1), from Mal'ta in south-central Siberia. [...] Similarly, we find autosomal evidence that MA-1 is basal to modern-day western Eurasians and genetically closely related to modern-day Native Americans, with no close affinity to east Asians. [...] Sequencing of another south-central Siberian, Afontova Gora-2 dating to approximately 17,000 years ago, revealed similar autosomal genetic signatures as MA-1, suggesting that the region was continuously occupied by humans throughout the Last Glacial Maximum.


Though MA-1 is slightly more Western than Eastern Eurasian genetically, it's actually intermediate and way outside the range of Modern Europeans and Caucasoids:

In the first two principal components, MA-1 is intermediate between modern western Eurasians and Native Americans, but distant from east Asians.


When it's included in an admixture analysis, it comes out as a mix of Western Eurasians and the different Eastern Non-Africans that it shares ancestry with:

The ancient samples appear to be mostly West Eurasian in their ancestry, although the hunter gatherers are also inferred to have greater or lesser extents of an eastern non-African (ENA) component lacking in Stuttgart. [...] We note that the ancestry proportions in ancient samples like MA1 are more likely explained by shared ancestry than admixture. This is more likely to explain the nearly three-way distribution of South Asian, West Eurasian and Native American (plus Northeast Siberian) ancestry proportions in MA1, than three-way admixture of established populations.


Admixture from MA1 (and AG2) is highest in Eastern Hunter-Gatherers (EHG), then Scandinavian Hunter-Gatherers (SHG), then Western Hunter-Gatherers (WHG):

Application of this methods highlights the impact of Ancient North Eurasian (ANE) ancestry related to the ~22,000 BCE Mal'ta 1 and ~15,000 BCE Afontova Gora 2 on populations living in Europe, the Americas, and Eastern Eurasia. Eastern Eurasians can be modelled as arrayed along a cline with different proportions of ANE ancestry, ranging from ~40% ANE in Native Americans matching previous findings, to no less than ~5-10% ANE in diverse East Asian groups including Han Chinese. We also document a cline of ANE ancestry across the east-west extent of Eurasia. Eastern Hunter Gatherers (EHG) derive ~3/4 of their ancestry from the ANE; Scandinavian hunter-gatherers (SHG) are a mix of EHG and WHG; and WHG are a mix of EHG and the Upper Paleolithic Bichon from Switzerland.


After Native Americans, then Siberians, it's Northern and Eastern Europeans that have the highest ANE admixture because they have the most EHG (which came mainly with Bronze Age migrations from the Russian Steppe):

We find that genetic affinity to MA-1 is greatest in two regions: first, the Americas; and second, northeast Europe and northwest Siberia, with north-to-south latitudinal clines in shared drift with MA-1 in both Europe and Asia.

(redder circles = more affinity, bluer = less)


Here's the genetic cline formed by Modern Europeans stretching from Caucasoid Neolithic Farmers (Stuttgart) towards ANE:

By using BedouinB instead of Stuttgart, we can also plot Stuttgart in the space of these statistics. Europeans uniformly share more drift with MA1 than with Karitiana, and form a cline in this space with slope >1. Karitiana, because of its Ancient North Eurasian ancestry was crucial in detecting the presence of such ancestry in Europeans but can now be replaced in the study of this ancestry by a better proxy for this ancestry (MA1).


---------------
Raghavan et al. "Upper Palaeolithic Siberian genome reveals dual ancestry of Native Americans". Nature, 2014.

Lazaridis et al. "Ancient human genomes suggest three ancestral populations for present-day Europeans". Nature, 2014.

Lazaridis et al. "Genomic insights into the origin of farming in the ancient Near East". Nature, 2016.

Related: Phenotypes of Hunters and Farmers

0 comments