Gammaglobulin groups of the Khoisan peoples of Southern Africa: evidence for polymorphism for a Gm1,5,13,14,21 haplotype among the San.

The Gm and Inv types were determined for eight San (Bushman) populations, two Khoikhoi (Hottentot) populations, one Coloured population, 112 San families in which the genotypes of the parents could be unambiguously determined, and for 65 San families in which the genotype of one or both parents could not be determined with certainty. The population and family data establish that the haplotype array of the San is composed of Gm1,21, Gm1,13, Gm1,5,13,14, and Gm1,5,13,14,21; Gm1,5,6 and Gm1,5,6,14 are also present but may have been acquired through admixture with Negroes. The Gm1,5,13,14,21 haplotype has not been found to be polymorphic in any other population. The haplotype array of the Khoikhoi is composed of Gm1,2,21, Gm1,13, and Gm1,5,13,14; Gm1,5,6 and Gm1,5,6,14 are also present but, as in the case of the San, may be due to admixture. The San and Khoikhoi differ from each other in that the former have the Gm1,21 and Gm1,5,13,14,21 haplotypes not present in the latter, and the Khoikhoi have the Gm1,2,21 haplotype not present in the San. These three haplotypes and Gm1,13 serve to distinguish the Khoisan people from other African peoples.