ORIGIN AND EVOLUTION OF NATIVE-AMERICAN MTDNA VARIATION - A REAPPRAISAL

The timing and number of prehistoric migrations involved in the settle ment of the American continent is subject to intense debate. Here, we reanalyze Native American control region mtDNA data and demonstrate th at only an appropriate phylogenetic analysis accompanied by an appreci ation of demographic factors allows us to discern different migrations and to estimate their ages. Reappraising 574 mtDNA control region seq uences from aboriginal Siberians and Native Americans, we confirm in a greement with linguistic, archaeological and climatic evidence that (i ) the major wave of migration brought one population, ancestral to the Amerinds, from northeastern Siberia to America 20,000-25,000 years ag o and (ii) a rapid expansion of a Beringian source population took pla ce at the end of the Younger Dryas glacial phase similar to 11,300 yea rs ago, ancestral to present Eskimo and Na-Dene populations.