Comparison of genetic and anthropological interpretations of population isolates in Aguacatenango, Chiapas, Mexico

Intensive demographic and genetic studies were made of Aguacatenango, a partial isolate population in Chiapas, Mexico. The census showed higher rates of birth than mortality, with a stable population maintained by emigration. Complete enumeration showed many discrepancies between the ideal and actual mating patterns. Though ideally an endogamous town, many marriages were to outsiders. Also many occurred between the two allegedly endogamous barrios of the town. Blood group determinations on a third of the population provided a second description of the isolate. This description suggested that although the population is nearly a homogeneous genetic unit, the elder residents of one barrio show genetic differences from those of the other. That the barrios might have indeed been genetic isolates was further suggested by a better fit to Hardy‐Weinberg equilibria for each barrio separately than for the isolate as a whole. These blood group data were compared to blood group data on one other isolate in the region revealing marked gene frequency differences. It is suggested that similar studies are needed on many populations if the effects of particular population structures on gene drift and selection are to be elucidated.