Abstract: | A demographic survey was conducted as part of an ongoing population study of large Mestizo and Indian communities in Tlaxcala, Mexico. Comparative data on population structure and movement, mate selection, age at marriage, differential fertility, and mortality were collected through the administration of a standardized demographic proforma, and then cross-tabulated by computer analysis. The resulting differences between the Indian and Mestizo populations are interpreted in terms of the relative importance of hybridization, natural selection, and genetic drift. Sizeable variance in achieved reproduction and the high neonatal mortality suggest the operation of natural selection in these two populations. Observed patterns of population movement and mate selection indicate that the Mestizo population of the city of Tlaxcala is highly hybridized, in contrast to the endogamous Indian community of San Pablo del Monte. |