Patterns of modern human diversification: Implications for Amerindian origins

Abstract

The study of modern human origins and the study of the origins of modern human diversity are intimately linked. The evolutionary models employed have implications both for interpreting the significance of morphological variation and evolutionary trends, and in terms of the processes that gave rise to such variation. Although controversial, available evidence is taken to indicate a single, recent origin of modern humans. This paper explores the process of differentiation of modern populations in Asia and argues for morphological discontinuities in the late Pleistocene populations in the region. The intensely studied population history of Eastern Asia suggests that the evolution of the Mongoloid population complex may result from a process of differentiations, expansions, and dispersals, resulting in the development of regional morphological patterns. The relatively late appearance of regional morphological differentiation, especially in Northeast Asia, opens the possibility of the earliest Amerindians not being a typical “Mongoloid” population. A more generalized Mongoloid morphology has been described for both North and South American Paleoindian remains. In this paper, the morphology of a robust, not typically Mongoloid, population in South America is investigated, and its implications for the homogeneity of Amerindians discussed. Since a derived, typically Mongoloid morphology cannot be attributed to the early Amerindian and Fueguian-Patagonian populations, it is argued either that the sinodont dental pattern was acquired in parallel in Asia and the Americas or that at least two migratory waves ancestral to Amerinds took place. © 1995 Wiley-Liss, Inc.