East-West cranial differentiation in pre-Columbian human populations of South America.
South Amerindians are frequently thought of as a rather biologically homogeneous megapopulation. However, when native South Americans are assessed by information coming from DNA variability analysis, they resolve into two, major distinct entities of Eastern and Western zones. The purpose of this study is to investigate if the same dual pattern emerges from craniometric data. We approached this question by means of functional craniometric variables. We found strong evidence that Westerners and Easterners constitute two distinct and independent microevolutionary universes when cranial morphology is assessed. The existence of a third universe, Northwest, cannot be completely ruled out, but needs further investigation. We also discovered that Westerners and Easterners present similar degrees of internal variation, contrary to the findings of geneticists and molecular biologists. Palaeoamericans seem to be more similar to Easterners than to Westerners and North-Westerners. Our results suggest that this East-West cranial differentiation is more probably the result of differential rates of genetic drift and gene flow acting on each side of the Cordillera. However, different intensities of gene flow between Palaeoamericans and Amerindians in the highlands and in the lowlands cannot be completely dismissed as a possible explanation for the differentiation found.
Pucciarelli
Héctor M
HM
Departamento Científico de Antropología del Museo de La Plata, Universidad Nacional de La Plata, 1900 La Plata, Argentina. hmpucci@fcnym.unlp.edu.ar
Neves
Walter A
WA
González-José
Rolando
R
Sardi
Marina L
ML
Rozzi
Fernando Ramírez
FR
Struck
Adelaida
A
Bonilla
Mary Y
MY
D016000:Cluster Analysis; D005843:Geography; D049690:History, Ancient; D006801:Humans; D008297:Male; D025341:Principal Component Analysis; D018401:Sample Size; D012886:Skull / Q000033:anatomy & histology* / Q000502:physiology*; D013020:South America