Beringian Ennui

I came across this article from the September issue of PLOS One quite by accident. I was checking out the latest issue of Four Stone Hearths, which is a monthly round up of blog Anthropology topics that maintains the American Boasian standard of a four-field approach when I saw a number of post related to this article. The article "Berinigian Standstill and Spread of Native American Founders" by Tamm et al. (2007) looks at complete mtDNA sequences in ~ 600 Native Americans and comes to the conclusion that there was a long occupation of Beringia of ~15,000 that occurred before the rapid colonization of the Americas along the Pacific coast, within the last 15,000 years. The article is worth a read and a number of other bloggers have commented on it including Remote Control, Gene Expression, and Anthopology.net.

While I agree with the idea of back migrations from the Americas to Siberia (the Inuit still live on both side of the Bering Sea) and higher resolution of Native American mtDNA founder sequences I am little unsure whether they the full mtDNA genome of all 600 individuals or did they just do high resolution RFLP analysis. In the abstract it states "20 new complete mtDNAs from the Americas and seven from Asia. This sequence data was used to direct high-resolution genotyping from 20 American and 26 Asian populations." so did they only completely sequence 27 mtDNAs and then direct the RFLP analysis from that. What populations were the 20 sequences from and how representative are they of all Native American populations. Just a few minor quips I had with the paper but overall an interesting read and one I'm sure that will stir some additional debate about the Pleistocene Occupation of the Americas. Here is the Abstract and some other info about the paper.

Beringian Standstill and Spread of Native American Founders

Erika Tamm¹, Toomas Kivisild^1,2, Maere Reidla¹, Mait Metspalu¹, David Glenn Smith³, Connie J. Mulligan⁴, Claudio M. Bravi⁵, Olga Rickards⁶, Cristina Martinez-Labarga⁶, Elsa K. Khusnutdinova⁷, Sardana A. Fedorova^1,8, Maria V. Golubenko^1,9, Vadim A. Stepanov⁹, Marina A. Gubina^1,10, Sergey I. Zhadanov^1,10,11, Ludmila P. Ossipova¹⁰, Larisa Damba^1,10, Mikhail I. Voevoda¹⁰, Jose E. Dipierri¹², Richard Villems¹, Ripan S. Malhi^13*

1 Department of Evolutionary Biology, University of Tartu, Estonian Biocentre, Tartu, Estonia, 2 Leverhulme Centre for Human Evolutionary Studies, University of Cambridge, Cambridge, United Kingdom, 3 Department of Anthropology, University of California at Davis, Davis, California, United States of America, 4 Department of Anthropology, University of Florida, Gainesville, Florida, United States of America, 5 Instituto Multidisciplinario de Biología Celular, La Plata, Argentina, 6 Department of Biology, University of Rome Tor Vergata, Rome, Italy, 7 Institute of Biochemistry and Genetics, Ufa Research Center, Russian Academy of Sciences, Ufa, Russia, 8 Department of Molecular Genetics, Yakut Research Center, Russian Academy of Medical Sciences, Yakutia, Russia, 9 Institute of Medical Genetics, Tomsk Research Center, Russian Academy of Medical Sciences, Tomsk, Russia, 10 Institute of Genetics and Cytology, Siberian Branch of Russian Academy of Sciences, Novosibirsk, Russia, 11 Department of Anthropology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America, 12 Instituto de Biologia de la Altura–Universidad Nacional de Jujuy, Jujuy, Argentina, 13 Department of Anthropology, Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Champaign, Illinois, United States of America

Abstract

Native Americans derive from a small number of Asian founders who likely arrived to the Americas via Beringia. However, additional details about the intial colonization of the Americas remain unclear. To investigate the pioneering phase in the Americas we analyzed a total of 623 complete mtDNAs from the Americas and Asia, including 20 new complete mtDNAs from the Americas and seven from Asia. This sequence data was used to direct high-resolution genotyping from 20 American and 26 Asian populations. Here we describe more genetic diversity within the founder population than was previously reported. The newly resolved phylogenetic structure suggests that ancestors of Native Americans paused when they reached Beringia, during which time New World founder lineages differentiated from their Asian sister-clades. This pause in movement was followed by a swift migration southward that distributed the founder types all the way to South America. The data also suggest more recent bi-directional gene flow between Siberia and the North American Arctic.