Wednesday, August 14, 2013

PreColumbian Migration to the Americas Was Very Complicated

Reconciling migration models to the Americas with the variation of North American native mitogenomes


1. Alessandro Achilli (a)
2. Ugo A. Perego (b,c)
3. Hovirag Lancioni (a)
4. Anna Olivieri (b)
5. Francesca Gandini (b)
6. Baharak Hooshiar Kashani (b)
7. Vincenza Battaglia (b)
8. Viola Grugni (b)
9. Norman Angerhofer (c)
10. Mary P. Rogers (d)
11. Rene J. Herrera (e)
12. Scott R. Woodward (c,f)
13. Damian Labuda (g)
14. David Glenn Smith (h)
15. Jerome S. Cybulski (i)
16. Ornella Semino (b)
17. Ripan S. Malhi (d,j)
18. Antonio Torroni (b)


a. Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, 06123 Perugia, Italy;

b. Dipartimento di Biologia e Biotecnologie “Lazzaro Spallanzani”, Università di Pavia, 27100 Pavia, Italy;

c. Sorenson Molecular Genealogy Foundation, Salt Lake City, UT 84115;

d. Department of Anthropology, University of Illinois, Champaign, IL 61801

e. Department of Biological Sciences, Florida International University, Miami, FL 33199;

f. AncestryDNA, Provo, UT 84604;

g. Département de Pédiatrie, Centre de Recherche du Centre Hospitalier Universitaire Sainte-Justine, Université de Montréal, Montréal, QC, Canada H3T 1C5;

h. Department of Anthropology, University of California, Davis, CA 95616; and

i. Canadian Museum of Civilization, Gatineau, QC, Canada K1A 0M8

j. Institute for Genomic Biology, University of Illinois, Champaign, IL 61801;


In this study we evaluated migration models to the Americas by using the information contained in native mitochondrial genomes (mitogenomes) from North America. Molecular and phylogeographic analyses of B2a mitogenomes, which are absent in Eskimo–Aleut and northern Na-Dene speakers, revealed that this haplogroup arose in North America ∼11–13 ka from one of the founder Paleo-Indian B2 mitogenomes. In contrast, haplogroup A2a, which is typical of Eskimo–Aleuts and Na-Dene, but also present in the easternmost Siberian groups, originated only 4–7 ka in Alaska, led to the first Paleo-Eskimo settlement of northern Canada and Greenland, and contributed to the formation of the Na-Dene gene pool. However, mitogenomes also show that Amerindians from northern North America, without any distinction between Na-Dene and non–Na-Dene, were heavily affected by an additional and distinctive Beringian genetic input. In conclusion, most mtDNA variation (along the double-continent) stems from the first wave from Beringia, which followed the Pacific coastal route. This was accompanied or followed by a second inland migratory event, marked by haplogroups X2a and C4c, which affected all Amerindian groups of Northern North America. Much later, the ancestral A2a carriers spread from Alaska, undertaking both a westward migration to Asia and an eastward expansion into the circumpolar regions of Canada. Thus, the first American founders left the greatest genetic mark but the original maternal makeup of North American Natives was subsequently reshaped by additional streams of gene flow and local population dynamics, making a three-wave view too simplistic.

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