Anti-Symmetry of First Upper Molar in Domestic Goats

Casanova PMP*

Abstract

Developmental instability theory suggests that variation in some body areas can partially reflect the ability to buffer development from key environmental and genetic perturbations. Developmental stability is defined as the ability of organisms to withstand genetic or environmental disturbances during development. Support for this approach comes mainly from assessment of fluctuating asymmetry - that is deviations from symmetry of body features that are symmetric at the population level. In order to compare developmental instability in domestic goats, we sampled 22 adult skulls. Length of upper molars (from M1 to M3), for each side, on their occlusal aspect, was measured and bilaterally compared using standard methods. Left-right differences in first upper molar (M1), which were not size-dependent, presented a platykurtic distribution. There was thus evidence of directional asymmetry towards the left side in M1.