The 81st Annual Meeting of the American Association of Physical Anthropologists (2012)

Scenarios for the early settlement of the Americas and the importance of recurrent gene flow with Asia


1Centro Nacional Patagónico, CONICET, 2Sede Puerto Madryn, Universidad Nacional de la Patagonia San Juan Bosco., 3Centro Nacional Patagónico, CONICET, 4Centro Nacional Patagónico, CONICET, 5Centro Nacional Patagónico, 6Centro Nacional Patagónico, CONICET

Friday 2:15-2:30, Grand Ballroom II Add to calendar

Different scenarios attempting to describe the initial phases of the human dispersal from Asia into the New World have been proposed during the last three decades. However, some aspects concerning the population affinities among early and modern Asians and Native Americans remain controversial. Specifically, contradictory views based mainly on partial evidence such as skull morphology or molecular genetics have led to hypotheses such as the ‘Two Waves/Components’ and ‘Single Wave’ or ‘Out of Beringia’ model, respectively. Alternatively, an integrative scenario considering both morphological and molecular variation has been proposed and named as the ‘Recurrent Gene-Flow’ hypothesis. This scenario considers a single origin for all the Native Americans, and local, within-continent evolution plus the persistence of contact among circum-Arctic groups. Here we analyze 2D geometric morphometric data to evaluate the associations between observed craniometric distance matrix and different geographic design matrices reflecting distinct scenarios for the peopling of the New World using basic and partial Mantel tests. Additionally, we calculated the rate of morphological differentiation between Early and Late American samples under the different settlement scenarios and compared our findings to the predicted morphological differentiation under neutral conditions. Also, we incorporated in our analyses some variants of the classical Single-Wave and Two-Waves models as well as the Recurrent Gene-Flow model. Our results suggest a better explanatory performance of the ‘Recurrent Gene Flow’ model, and provide additional insights concerning affinities among Asian and Native American circum-Arctic groups.

This work was supported by fellowships from Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET, PIP 2008 112-200801-02850) and Agencia Nacional de Promoción Científica y Tecnológica (PICT 2007-01585), Argentina.

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