Evolution of the dentition in prehistoric Ohio Valley Native Americans: II. Morphology of the deciduous dentition.

In order to evaluate the microevolutionary dynamics of morphological features of the deciduous dentition, I collected data on the variation of 57 features (33 crown and 24 root) from prehistoric Ohio Valley populations. I sampled a total of 370 individuals from 26 populations representing a lineage that inhabited the middle and upper Ohio valley region from approximately 3000 to 350 BP. Evolutionary changes in the frequencies of morphological features of the deciduous teeth in this lineage were limited. Over 80% of the features show no significant differences among the populations. The relatively few features that show consistent differences separate pre- and postmaize agricultural populations. I discuss explanations for this change in terms of selection differences or gene flow. The general pattern of morphological trait expression in the deciduous teeth of this Ohio Valley lineage corresponds to what has been termed the Mongoloid dental complex (sinodonty in the permanent teeth). I suggest additional features that, with further study, may be added to this morphological complex.