Distinctive Paleo-Indian Migration Routes from Beringia Marked by Two Rare mtDNA Haplogroups

Distinctive Paleo-Indian Migration Routes from Beringia Marked by Two Rare mtDNA Haplogroups

It is widely accepted that the ancestors of Native Americans arrived in the New World via Beringia approximately 10 to 30 thousand years ago (kya). However, the arrival time(s), number of expansion events, and migration routes into the Western Hemisphere remain controversial because linguistic, archaeological, and genetic evidence have not yet provided coherent answers. Notably, most of the genetic evidence has been acquired from the analysis of the common pan-American mitochondrial DNA (mtDNA) haplogroups. In this study, we have instead identified and analyzed mtDNAs belonging to two rare Native American haplogroups named D4h3 and X2a. Phylogeographic analyses at the highest level of molecular resolution (69 entire mitochondrial genomes) reveal that two almost concomitant paths of migration from Beringia led to the Paleo-Indian dispersal approximately 1517 kya. Haplogroup D4h3 spread into the Americas along the Pacific coast, whereas X2a entered through the ice-free corridor between the Laurentide and Cordilleran ice sheets. The examination of an additional 276 entire mtDNA sequences provides similar entry times for all common Native American haplogroups, thus indicating at least a dual origin for Paleo-Indians. A dual origin for the first Americans is a striking novelty from the genetic point of view, and it makes plausible a scenario positing that within a rather short period of time, there may have been several entries into the Americas from a dynamically changing Beringian source. Moreover, this implies that most probably more than one language family was carried along with the Paleo-Indians.


I’m curious.. did they find a parent for X2a in East Asia? As far as I know the only possible HG ancestral to it is on the West coast of Europe. I shall have to check up.


One response to “Distinctive Paleo-Indian Migration Routes from Beringia Marked by Two Rare mtDNA Haplogroups

  1. I’m curious.. did they find a parent for X2a in East Asia?

    AFAIK not. X2a is one of the six subclades of X2 and all of the others are in West Eurasia/North Africa (as well as all X1, which is typically North African). The only exception is some Altaian X2 but doesn’t seem particularly related to the American one.

    I can only think that some X2 was involved in Siberian demographics (maybe but not necesarily in relation with Y-DNA Q) but that has gone extinct since then, while in Beringia experienced some founder effect instead that allowed it to perist and even expand into the Clovis migration.

    It is noticeable that Na-Dene, the liguistic family most likely related to Clovis, has recently been “demonstrated” to be closely related to Yenisean (Ket and other now extinct languages). Kets are strong in Y-DNA Q and while they don’t seem to have mtDNA X, they do nevertheless fashion some other unnamed but old subclade of N (ref). So, in my understanding it is very possible that various rare N subclades may have been once somewhat common in North Asia and have since vanished (the demographic peculiarities of the region and the extensive genocide of Siberians, way too similar to the one suffered by Native Americans or Australian Aborigines would explain how).

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