East-West cranial differentiation in pre-columbian human populations of South America

HECTOR PUCCIARELLI,; WALTER NEVES,; GONZÁLEZ-JOSÉ, ROLANDO; MARINA SARDI,; RAMÍREZ ROZZI, FERNANDO; ADELAIDA STRUCK,; MARY Y BONILLA,

Homo

Año: 2006 vol. 57 p. 133 - 150

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, as well, 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 what has been found by geneticists and molecular biologists. Paleoamericans 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 Paleoamericans and Amerindians in the Highlands and in the Lowlands cannot be completely dismissed, as well, as possible explanation for the differentiation found.