A comparison of the genetic infrastructure of the Ye'cuana and the Yanomama: a likelihood analysis of genotypic variation among populations

A general procedure is described for measuring and testing population differences in gametic frequencies. The total dispersion among populations is subdivided in hierarchial fashion. The multiple-locus treatment is simply the sum of the single-locus analysis, provided gametic equilibrium obtains among the loci. In the event that gametic equilibrium does not obtain, correlations among loci need to be dealt with. The analysis is then used to examine the genetic infrastructure of two Indian tribes from South America, the Ye'cuana (Makiritare) and the Yanomama. From historical evidence, we may identify several 'clusters' of villages within each tribe. The demographic and cultural practices affecting village formation and the maintenance of peer integrity are rather different in these tribes, however, and lead us to postulate rather different patterns of genetic variation among villages. Analyses of five codominant two-allele loci, four dominant two-allele loci and two complex loci (with four codominant haplotypes each) demonstrate that Yanomama clusters are more disparate than Ye'cuana clusters, as would have been predicted on socio-cultural grounds.