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


Geometric morphometric analysis of the upper first molar in modern hunter-gatherer populations

ALEJANDRO ROMERO1, FERNANDO V. RAMIREZ ROZZI2, MAITE ARTERO3, STÉPHANIE TORRIJO1, NURIA LÓPEZ1, JOAQUÍN DE JUAN1 and ALEJANDRO PÉREZ-PÉREZ3.

1Department of Biotechnology, University of Alicante (Spain), 2UPR 2147, Dynamique de l’évolution humaine, CNRS, Paris (France), 3Department of Animal Biology, University of Barcelona (Spain)

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Tooth morphology shows a large variability; however it remains unclear which is the relation, if any, between it and environmental conditions. In this exploratory work we start to observe if tooth morphology varies following large climatic conditions. The morphology of upper first molar (M1) of six modern hunter-gatherer populations from hot-humid (n=18; Central African Baka-Aka pygmies and Andaman islanders), hot-dry (n=20; South African Khoesan and south-western Australian Aborigines) and cold-humid (n=17; Greenland Inuit and Yamana from Tierra del Fuego) climates was analysed by Principal components analysis (PCA) of Procrustes shape coordinates and by canonical variates (CV). The PCA of the relative warp scores shows that populations living in cold-humid environments characterize by an expanded and square occlusal polygon with a reduced hypocone, whereas those inhabiting in hot (dry and humid) climates present a bigger hypocone and a reduction in the distance between the protocone and the hypocone. Changes in shape are not allometric. The canonical analysis enables to distinguish clearly the Inuit from Yamana (Goodall’s F-test P<0.001). Populations from hot climates distribute along the first CV axe (41.3% of the total variance), Khoesan differs from SW Australian Aborigines (P<0.001) and Andaman islanders distinguish from Baka-Aka pygmies (P<0.001). This work is only based on a single tooth class and random factors cannot be disregarded, however the results seem to suggest that differences in the morphology of the upper M1 are not related to climatic conditions and others factors can probably better explain it.

This study was funded by Spanish GV and MEC, grant numbers BEST/2009/258, CGL2010-15340, CGL2011-22999.

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