The history of the North African mitochondrial DNA haplogroup U6 gene flow into the African, Eurasian and American continents.

Bernard Secher,Ana M González,José M Larruga,Phillip Endicott,Rosa Fregel,Vicente M Cabrera,José J Pestano

doi:10.1186/1471-2148-14-109

Bernard Secher, Ana M González + Show 5 more

Open Access

https://doi.org/10.1186/1471-2148-14-109

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Abstract

BackgroundComplete mitochondrial DNA (mtDNA) genome analyses have greatly improved the phylogeny and phylogeography of human mtDNA. Human mitochondrial DNA haplogroup U6 has been considered as a molecular signal of a Paleolithic return to North Africa of modern humans from southwestern Asia.ResultsUsing 230 complete sequences we have refined the U6 phylogeny, and improved the phylogeographic information by the analysis of 761 partial sequences. This approach provides chronological limits for its arrival to Africa, followed by its spreads there according to climatic fluctuations, and its secondary prehistoric and historic migrations out of Africa colonizing Europe, the Canary Islands and the American Continent.ConclusionsThe U6 expansions and contractions inside Africa faithfully reflect the climatic fluctuations that occurred in this Continent affecting also the Canary Islands. Mediterranean contacts drove these lineages to Europe, at least since the Neolithic. In turn, the European colonization brought different U6 lineages throughout the American Continent leaving the specific sign of the colonizers origin.

Highlights

Complete mitochondrial DNA genome analyses have greatly improved the phylogeny and phylogeography of human mtDNA
Using mtDNA restriction polymorphisms, it was first proposed that all extant modern humans have a recent African origin [2]; a hypothesis that found physical anchorage in the paleoanthropological record [3,4]
Additional file 2 shows the U6 phylogenetic tree based on 230 complete sequences

Summary

Introduction

Complete mitochondrial DNA (mtDNA) genome analyses have greatly improved the phylogeny and phylogeography of human mtDNA. Human mitochondrial DNA haplogroup U6 has been considered as a molecular signal of a Paleolithic return to North Africa of modern humans from southwestern Asia. After the first spread out of Africa, one of the most important modern human movements was a Paleolithic back-flow to Africa. Clear signals of this return were deduced from the phylogeny and phylogeography of the mtDNA haplogroups U6 [5,6,7,8,9] and M1 [5,7,8,10], which show major North and East African distributions. The genealogy and geographic distribution of at least two African branches of the West-Eurasian Y-chromosome haplogroups R and T (R-V88 and T-M70, respectively) [11,12,13], gave additional evidence for this back migration from a paternal perspective

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