The Effects of Sexual Dimorphism, Asymmetry, and Intertrait Association on the Distribution of Thirteen Deciduous Dental Nonmetric Traits in a Sample of Pima Amerindians

Abstract

One hundred dental casts of modern Pima Amerindian children, 50 male and 50 female, were examined for the presence and expression of thirteen deciduous nonmetric traits. The effects of sexual dimorphism, asymmetry, and inter-trait association on trait presence were examined to evaluate their utility in population distance studies. No statistically significant differences between the sexes were observed. The majority of examined variants displayed a strong trend toward bilateral expression and no statistically significant differences between antimeres occurred. These data support the hypothesis that strong genetic components coupled with negligible environmental influences are involved in deciduous trait presence. Five statistically significant associations between variants were detected. Four of these involved a combination of incisor and canine shoveling within and between jaws. This indicates that their combined use in biological distance studies violates the mathematical assumption of independence. The lack of significant sexual dimorphism and asymmetry in the deciduous discrete traits examined herein supports their use in population distance analyses if precautions are taken to use non-associated traits.