Demographic and genetic relationships among Brazilian Wapishana Indians.

Demographic information is given and data on 25 genetic systems are reanalysed for six populations of Wapishana Indians living in northern Brazil. Despite 200 years of contact with non-Indians, the maximum amount of admixture that may be present in persons who claim 'pure' Indian ancestry is 3%. Historical sources mention considerable exchange with the Macushi, Taurepan and Atorai tribes, confirmed by our genealogies. Departures from the maximum amount of heterozygosity per locus are similar in putative 'full bloods' and admixed individuals, as well as among the first and members of other tribes. Demographically the Wapishana can be characterized as very mobile, with high fertility but moderate mortality for an agricultural group. The Index of Opportunity for Selection (0 x 57) is one of the lowest calculated so far among South American tribes. Despite the indicated high mobility, clustering of some alleles was observed in two localities.