Mitochondrial lineage C1d in South America questions the two migrations hypothesis

An interesting new paper for those interested in the process of colonization of America.

Hugo A. Perego et al. The initial peopling of the Americas: A growing number of founding mitochondrial genomes from Beringia. Genomic Research, 2010. Open access.


Abstract

Pan-American mitochondrial DNA (mtDNA) haplogroup C1 has been recently subdivided into three branches, two of which (C1b and C1c) are characterized by ages and geographical distributions that are indicative of an early arrival from Beringia with Paleo-Indians. In contrast, the estimated ages of C1d—the third subset of C1—looked too young to fit the above scenario. To define the origin of this enigmatic C1 branch, we completely sequenced 63 C1d mitochondrial genomes from a wide range of geographically diverse, mixed, and indigenous American populations. The revised phylogeny not only brings the age of C1d within the range of that of its two sister clades, but reveals that there were two C1d founder genomes for Paleo-Indians. Thus, the recognized maternal founding lineages of Native Americans are at least 15, indicating that the overall number of Beringian or Asian founder mitochondrial genomes will probably increase extensively when all Native American haplogroups reach the same level of phylogenetic and genomic resolution as obtained here for C1d.

Fig. 2
In parenthesis percentage of sequences at SMGF database,
from which the regional apportions are deduced

Update: Speaking to La Voz de Galicia[es], one of the co-researchers, Antonio Salas, claims that the molecular clock estimates they got imply not only that the Paleolithic colonization of America happened between 15 and 18 thousand years ago but also that the colonists spread extremely rapidly across the double continent: in less than one thousand years (found at Pileta de Prehistoria).