West Asian sources of the Eurasian component in Ethiopians: a reassessment

Ludovica Molinaro,Francesco Montinaro,Davide Marnetto,Toomas Kivisild,Doron M Behar,Luca Pagani,Burak Yelmen

doi:10.1038/s41598-019-55344-y

Ludovica Molinaro, Francesco Montinaro + Show 5 more

Open Access

https://doi.org/10.1038/s41598-019-55344-y

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Abstract

The presence of genomic signatures of Eurasian origin in contemporary Ethiopians has been reported by several authors and estimated to have arrived in the area from 3000 years ago. Several studies reported plausible source populations for such a signature, using haplotype based methods on modern data or single-site methods on modern or ancient data. These studies did not reach a consensus and suggested an Anatolian or Sardinia-like proxy, broadly Levantine or Neolithic Levantine as possible sources. We demonstrate, however, that the deeply divergent, autochthonous African component which accounts for ~50% of most contemporary Ethiopian genomes, affects the overall allele frequency spectrum to an extent that makes it hard to control for it and, at once, to discern between subtly different, yet important, Eurasian sources (such as Anatolian or Levant Neolithic ones). Here we re-assess pattern of allele sharing between the Eurasian component of Ethiopians (here called “NAF” for Non African) and ancient and modern proxies. Our results unveil a genomic legacy that may connect the Eurasian genetic component of contemporary Ethiopians with Sea People and with population movements that affected the Mediterranean area and the Levant after the fall of the Minoan civilization.

Highlights

The presence of genomic signatures of Eurasian origin in contemporary Ethiopians has been reported by several authors and estimated to have arrived in the area from 3000 years ago
To determine the most likely source of the Eurasian gene flow into the ancestral gene pool of present-day Ethiopians we have used a combination of ancestry deconvolution (AD) and allele sharing methods as previously proposed elsewhere[6]
Our analyses aimed at describing the non African component of Ethiopians as a combination of available ancient ones, and we stress our results should not be interpreted as involving a direct connection or descent line between Neolithic Anatolia and Ethiopia

Summary

Introduction

The presence of genomic signatures of Eurasian origin in contemporary Ethiopians has been reported by several authors and estimated to have arrived in the area from 3000 years ago. Several studies reported plausible source populations for such a signature, using haplotype based methods on modern data or single-site methods on modern or ancient data These studies did not reach a consensus and suggested an Anatolian or Sardinia-like proxy, broadly Levantine or Neolithic Levantine as possible sources. That the deeply divergent, autochthonous African component which accounts for ~50% of most contemporary Ethiopian genomes, affects the overall allele frequency spectrum to an extent that makes it hard to control for it and, at once, to discern between subtly different, yet important, Eurasian sources (such as Anatolian or Levant Neolithic ones). That the deeply divergent, autochthonous African component which accounts for ~50% of most contemporary Ethiopian genomes may affect their overall allele frequency spectrum This would make it hard to discern between subtly different, yet important, Eurasian sources (such as Anatolian or Levant Neolithic ones). Our results demonstrate that such an approach is viable, virtually unbiased and that the results we obtain are qualitatively different and informative on the Iron Age populations that brought a distinctive Eurasian component to North-East Africa

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