This study will be conducted using four Mexican populations which originated in the valley of Tlaxcala. Serologic, dermatoglyphic, anthropometric and demographic data have already been collected and analyzed for these populations. The primary objective is an investigation of dental genetics, specifically the relative roles of genetics and environment in dental formation. Other objectives include 1) the determination of the evolutionary divergence of transplanted populations, 2) the assessment of gene flow from Spanish populations to Indian populations, 3) an analysis of the heritability of odontometric and discrete traits, and 4) the establishment of the degree of correspondence between odontometrics and discrete traits in the calculation of genetic distances. The methodology includes the additional collection of dental casts, the measurement of mesiodistal and buccolingual diameters and determination of discrete traits. The data will be analyzed using univariate and multivariate statistical techniques, including step wise discriminant analysis and factor analysis, as well as heritability estimates. BIBLIOGRAPHIC REFERENCES: O'Rourke, D. and M. H. Crawford, 1976. Odontometric analysis of adult dentitions of four Tlaxcaltecan populations. In: The Tlaxcaltecans: Ethnohistory, Demography, Morphology and Genetics (Ed. M.H. Crawford), Univ. of Kansas Anthropology Series, Chapter 15. Lin, P.H. 1976. Factor Analysis of dentition of three Tlaxcaltecan populations. In: The Tlaxcaltecans: Ethnohistory, Demography, Morphology and Genetics (Ed. M.H. Crawford), Univ. of Kansas Anthropology Series, Chapter 16.