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

Detecting modular components on human skull: implications to the structuring of global human cranial variation


1School of Odontology of São José dos Campos, Unesp - Universidade Estadual Paulista "Júlio de Mesquita Filho", 2Laboratory for Human Evolutionary Studies, Depatment of Genetics and Evolutionary Biology, Biosciences Institute, University of São Paulo, 3Children's Institute, School of Medicine of University of São Paulo

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In the last decades several studies are showing that morphological integration and modularity are important points of intersection between evolution and the development of organisms. These studies are particularly abundant on debate about the nature of the morphological integration and modularity of skull. However, few of these studies have showed how this hierarchical nature can explain the worldwide variation observed among human skulls. In this study we explore the pattern of correlation and covariation of cranial morphology of 17 populations dispersed along six great geographic regions of the world to investigate if the human cranial observed variation can be described in terms of modular differentiation and if it could be considered a relative predictor to the acquaintance of the global structuring. To achieve our goal we constructed correlations and covariances matrices over 47 craniometric variables of 981 individuals from classical Howell’s databank, divided in two different hierarchical levels: populational and regional (continental). An extra meta-population containing all individuals of the sample was used as control. The modules were detected by comparison of these matrices. The results obtained by our investigation show that the populations studied presents strong modular similarity within great regions and some markedly modular differentiations and disproportions between these great regions. In despite of the small sampling and the technical deficiencies of our methodology, our results suggests that the human cranial variation should be evolved partly rather by means of selective pressures than stochastic processes and also should have responded differently to these pressures.

FAPESP - São Paulo Research Foundation 08/58729-8

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