A very related previous blog entry on East-west cranial differences of South Americans. Also read a major study on Native American genetic variation. Also of interest, the Peopling of the Americas, and New synthesis on the first arrivals into the New World. Directly related to the issue of East-West differentiation in the Americas is the post on South American mtDNA, re-interpretation of its prehistory.
Journal of Human Evolution Volume 54, Issue 3, March 2008, Pages 296-308
East-West cranial differentiation in pre-Columbian populations from Central and North America
Héctor M. Pucciarelli
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 14,000 km 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.