The dentition of American Indians: Evolutionary results and demographic implications following colonization from Siberia

Abstract

This chapter uses dental morphology to make inferences about how the New World was first colonized. The major emphasis is on the initial Macro-Indian migration based on dental traits observed in Paleo-Indian, Archaic, and more recent prehistoric crania. Themajor results are as follows: (1) Arctic and Subarctic native dentitions differ enough from those of Macro-Indians to indicate separate migrations. (2) Clustered MMD values show three Macro-Indian branches of North Americans, South Americans, and mixed North and South. (3) There is no marked branching depth for these three dental divisions, which fits the hypothesis of a single rapid Paleo-Indian colonization event. (4) The minimally divergent North and South American dental divisions are most likely the microevolutionary result of dispersal-dependent population structure and lineage effects. (5) No genetic bottlenecking can be identified at Panama. (6) The small amount of New World internal dental divergence favors colonization of South America soon after the settlement of North America. (7) There are no obvious clines, frequency trends, or geographic groupings for individual dental traits. This suggests little or no selection and that after leaving Siberia, population size increased sufficiently to limit genetic drift. (8) There is no sign of any Old World or Oceanic dental pattern other than Northeast Asian Sinodonty. All things considered, including New World and Siberian linguistics, archaeology, genetics, route considerations, and relevant natural history, dental analysis supports the Late Pleistocene ice-free corridor, Clovis or epi-Clovis settlement hypothesis, and the Greenberg Amerind or Macro-Indian language evolution model.