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'Divorcing the Late Upper Palaeolithic demographic histories of mtDNA haplogroups M1 and U6 in Africa'
Erwan Pennarun, Toomas Kivisild, Ene Metspalu, Mait Metspalu, Tuuli Reisberg, Doron M Behar, Sacha C Jones and Richard Villems
BMC Evolutionary Biology 2012, 12:234
A Southwest Asian origin and dispersal to North Africa
in the Early Upper Palaeolithic era has been inferred in
previous studies for mtDNA haplogroups M1 and U6.
Both haplogroups have been proposed to show similar
geographic patterns and shared demographic histories.
We report here 24 M1 and 33 U6 new complete mtDNA
sequences that allow us to refine the existing
phylogeny of these haplogroups. The resulting
phylogenetic information was used to genotype a
further 131 M1 and 91 U6 samples to determine the
geographic spread of their sub-clades. No southwest
Asian specific clades for M1 or U6 were discovered. U6
and M1 frequencies in North Africa, the Middle East and
Europe do not follow similar patterns, and their sub-
clade divisions do not appear to be compatible with
their shared history reaching back to the Early Upper
Palaeolithic. The Bayesian Skyline Plots testify to non-
overlapping phases of expansion, and the haplogroups'
phylogenies suggest that there are U6 sub-clades that
expanded earlier than those in M1. Some M1 and U6
sub-clades could be linked with certain events. For
example, U6a1 and M1b, with their coalescent ages
of ~20,000-22,000 years ago and earliest inferred
expansion in northwest Africa, could coincide with the
flourishing of the Iberomaurusian industry, whilst U6b
and M1b1 appeared at the time of the Capsian culture.
Our high-resolution phylogenetic dissection of both
haplogroups and coalescent time assessments suggest
that the extant main branching pattern of both
haplogroups arose and diversified in the mid-later Upper
Palaeolithic, with some sub-clades concomitantly with
the expansion of the Iberomaurusian industry. Carriers
of these maternal lineages have been later absorbed
into and diversified further during the spread of Afro-
Asiatic languages in North and East Africa.