The Uto-Aztecan Premolar Among North and South Amerindians: Geographic Variation and Genetics

The Uto-Aztecan premolar (UAP) is adental polymorphism characterized by an exaggerated distobuccalrotation of the paracone in combination with thepresence of a fossa at the intersection of the distal occlusalridge and distal marginal ridge of upper first premolars.This trait is important because, unlike other dental variants,it has been found exclusively in Native Americanpopulations. However, the trait’s temporal and geographicvariation has never been fully documented. The discoveryof a Uto-Aztecan premolar in a prehistoric skeletal seriesfrom northern South America calls into question the presumedlinguistic and geographic limits of this trait. Weexamined published and unpublished data for this rarebut highly distinctive trait in samples representing over5,000 Native Americans from North and South America.Our findings in living Southwest Amerindian populationscorroborate the notion that the variable goes beyond thebounds of the Uto-Aztecan language family. It is found inprehistoric Native Americans from South America, easternNorth America, Northern and Central Mexico, and in livingand prehistoric populations in the American Southwestthat are not members of the Uto-Aztecan languagestock. The chronology of samples, its geographic distribution,and trait frequencies suggests a North American origin(Southwest) for UAP perhaps between 15,000 BP and4,000 BP and a rapid and widespread dispersal into SouthAmerica during the late Holocene. Family data indicatethat it may represent an autosomal recessive mutationthat occurred after the peopling of the Americas as its geographicrange appears to be limited to North and SouthAmerindian populations. Fil: Delgado Burbano, Miguel Eduardo. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Antropología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina Fil: Richard Scott, G.. University of Arizona; Estados Unidos