Comparing Biodistance Estimates from Deciduous and Permanent Dental Morphology in the Pre-Spanish US Southwest

Abstract

Biodistance analysis using dental nonmetric traits is a key method to examine population structure in the past. Researchers often favor permanent teeth rather than deciduous dentitions when examining biodistance in archaeological assemblages, despite being correlated. We compare the results of biodistance analyses using 79 permanent and 32 deciduous dental morphological traits from the ancestral remains of 351 individuals with permanent teeth and 122 individuals with deciduous teeth from the pre-Spanish Southwest United States. Biodistance was estimated between six regions based on the archaeological sites where individuals were found: Chaco, Gallina, La Plata, Middle Rio Grande, Mogollon, and Northern Rio Grande. Observations were first dichotomized, then traits were compared using tetrachoric correlation. Distance matrices of mean measure of divergence were then compared using a Mantel test. Biodistance estimates were similar between deciduous and permanent dentitions (r = 0.55, p < 0.05). Deciduous traits are thought to be a better reflection of underlying genetic variation since they are less impacted by environmental stress. Therefore, they may reveal additional trends that are hidden when only studying permanent teeth. We suggest researchers consider both the deciduous and permanent dentitions when using biodistance to more fully understand population structure.