| Summary: | The "Tripartite" model of the peopling of the New World presents the hypothesis that all Native American linguistic, dental, and genetic variation was the result of three migratory "waves" from northeast Asia, whose descendants are modern Amerindian, Na-Dene, and Aleut-Eskimo populations. Several hypotheses were derived from this model, and tested using dental morphological and metric traits from middle Holocene (5,000 - 8,000 yr B.P.) Amerindians: (1) all middle Holocene groups share dental traits with northern Asian "Sinodont" populations, reflecting their origin from a northern Asian founding population; (2) middle Holocene Amerindians exhibit close biological affinity with later Holocene Amerindians, followed by other New World populations and northern Asians, reflecting the historical sequence of divergence among these groups; (3) early Amerindian dental variation is limited due to late Pleistocene founding events. Dental metric and nonrnetric traits, known to be under strong genetic control, were recorded for 573 middle Holocene individuals from nine sites in eastern North America. All data were corrected for age and sex variation and observer error, and were tested using a wide range of statistical methods. Results were compared to expected patterns of variation from simulations of various evolutionary forces such as genetic drift and gene flow. The dental phenotypic homogeneity of Amerindians is not clearly not supported by analyses of middle Holocene metric and nonimetric dental traits. Nonmetric traits exhibit significant among-group variation, as do metric trait means. Discriminant function results and plots of biological distances reveal that middle Holocene skeletal samples do not have strong affinities with other North American or Asian populations. When middle Holocene samples were forced into one of the three New World subgroups (Aleut-Eskimo, Na-Dene, and Amerindian), they were classified as Amerindians. However, plots of biological distances revealed no clear three-way division of populations ...
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