Abstract

LOTTO, Federico P  and  GONZALEZ, Paula N. Inestabilidad del desarrollo en estructuras cráneo-faciales de poblaciones humanas sudamericanas. Rev Arg Antrop Biol [online]. 2014, vol.16, n.1, pp.17-29. ISSN 1514-7991.

Regulatory mechanisms acting on the effect of stochastic perturbations during development can be modulated by diverse environmental and genetic factors, resulting in increased developmental instability (DI) and individual variation. It has been suggested that subsistence-related ecological changes could have significantly influenced craniofacial morphology of South American aboriginal populations. In this paper, the magnitude and pattern of fluctuating asymmetry, used as a DI measure, are compared among the samples with different subsistence strategies and among 3 craniofacial modules. Midline and bilateral 3D landmarks were recorded in 109 skulls from Chubut, San Juan and SW of the Pampean region. The Generalized Procrustes Superimposition method was used to extract the symmetric and asymmetric components of shape. Preliminary analyses show that measurement error and directional asymmetry account for a reduced amount of total variation, while FA explains 10 to 15% of it. FA magnitude -estimated as the Procrustes distances between the original configurations and their reflections- found in the vault and facial region was higher for San Juan sample, while the cranial base did not show any differences among samples. Shape patterns in the asymmetric component show that Chubut sample is different from the others as regards cranial base and facial configurations, while San Juan is different in relation to vault. Results suggest modular variation in skull DI and differences among the analyzed samples.

Keywords : Fluctuating asymmetry; Geometric morphometrics; Developmental instability; Subsistence.

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