Discrete dental traits in four Tlaxcaltecan Mexican populations.

Seven hundred dental casts from four Tlaxcaltecan Indian populations of Mexico were analyzed for the incidence of ten discrete dental traits. The populations are of known historical origin, with Cuanalan and Saltillo transplanted from the Valley of Tlaxcala approximately 400 years ago. Given this temporal and geographical separation of these transplanted populations from the parental gene pool, statistically significant morphological divergence was observed. However, varying degrees of admixture with Spanish and possibly African colonists have complicated the interpretation of the results. Shovelling of incisors was shown to be the best discriminator of group differences. Mandibular molar patterns and mandibular incisor extension indicate that Cuanalan is closest to Saltillo while the valley communities. Tlaxcala and San Pablo, are closest to each other.