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, wereexamined 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 populationdistance studies. No statistically significant differences between the sexes were observed. The majority of examinedvariants displayed a strong trend toward bilateral expression and no statistically significant differences betweenantimeres occurred. These data support the hypothesis that strong genetic components coupled with negligibleenvironmental influences are involved in deciduous trait presence. Five statistically significant associations betweenvariants were detected. Four of these involved a combination of incisor and canine shoveling within and betweenjaws. This indicates that their combined use in biological distance studies violates the mathematical assumption ofindependence. The lack of significant sexual dimorphism and asymmetry in the deciduous discrete traits examinedherein supports their use in population distance analyses if precautions are taken to use non-associated traits.