East-West cranial differentiation in pre-Columbian populations from Central and North America

División Antropología del Museo de La Plata (FCNyM, UNLP), Paseo del Bosque s/n, 1900 La Plata, Argentina.
Journal of Human Evolution (Impact Factor: 3.73). 04/2008; 54(3):296-308. DOI: 10.1016/j.jhevol.2007.08.011
Source: PubMed


In a recent study we found that crania from South Amerindian populations on each side of the Andes differ significantly in terms of craniofacial shape. Western populations formed one morphological group, distributed continuously over 14,000km from the Fuegian archipelago (southern Chile) to the Zulia region (northwestern Venezuela). Easterners formed another group, distributed from the Atlantic Coast up to the eastern foothills of the Andes. This differentiation is further supported by several genetic studies, and indirectly by ecological and archaeological studies. Some authors suggest that this dual biological pattern is consistent with differential rates of gene flow and genetic drift operating on both sides of the Cordillera due to historical reasons. Here we show that such East-West patterning is also observable in North America. We suggest that the "ecological zones model" proposed by Dixon, explaining the spread of the early Americans along a Pacific dispersal corridor, combined with the evolution of different population dynamics in both regions, is the most parsimonious mechanism to explain the observed patterns of within- and between-group craniofacial variability.

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    • "Not only was a difference noted across environments, but also as one moved east to west. A similar east-west gradient was noted by both Pucciarelli et al. (2006, 2008), who examined variation across both North and South America, and Rothhammer & Silva (1989), who noted change moving from northwest South America towards the southeastern region. In order to assess inter-cemetery variation at Pacatnamu on the North Coast of Peru, Verano (1987) examined comparative samples from coastal and highland populations in relation to a sample from Pacatnamu and found that highland and coastal groups were distinct from one another and that geographic distance between samples correlated with biological distance. "
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