THE POPULATION STRUCTURE OF THE PERUVIAN CASHINAHUA: DEMOGRAPHIC, GENETIC AND CULTURAL INTERRELATIONSHIPS

The age and sex distribution of the Peruvian Cashinahua, an isolate of the tropical rain forest of 206 individuals, is similar to that of other groups of comparable ecologies and size. Their fertility ratio is the highest yet reported for any population, with a greater average number of offspring contributed per male than per female due to their polygynous marriage pattern. Though there are deviations from the preferred pattern of marriage, village endogamy remains high and serves to restrict inter-village gene flow. The estimated variance due to genetic drift is high, as would be expected under these conditions and is an effective force in gene frequency change between successive generations.