Abstract This study utilizes the GM/KM immunoglobulin allotype system to elucidate the phylogenetic relationships of sub-Saharan Africans. The importance of understanding the relatedness of these peoples stems from the sub-Saharan region being the possible birthplace of humans. Haplotype distributions were determined for 19 populations and compared using chi-square analysis. Published data of other sub-Saharan Africans and representative populations worldwide were also added for comparison. Genetic distances between populations were calculated based on haplotype frequencies, and genetic relationships were observed through principal components analysis. Data from the GM/KM system showed a genetic homogeneity of the Bantu populations, with some exceptions, supporting the possibility of a common origin of these peoples. The Malagasy appeared as a divergent population, most likely due to Southeast Asian/Austronesian admixture, as indicated by the presence of the GM*AF B haplotype. The Cape Coloured also showed a divergence, with their genetic structures containing Caucasoid and Khoisan contributions. Finally, the Mbuti Pygmies appeared genetically isolated and had the highest frequency of the GM*A B haplotype out of all studied populations.

KEY WORDS: HUMAN POPULATION GENETICS, IMMUNOGLOBULIN ALLOTYPING, PHYLOGENETICS, SOUTH AFRICA, SUB-SAHARAN AFRICA

Sub-Saharan Africa is of interest in archeological and evolutionary thought because this region is the possible birthplace of humankind (Hiernaux 1975; Nurse et al. 1985). Sub-Saharan Africa is also enmeshed in the controversy over the origin of modern humans with the debate over the "monophyletic" or "out-of-Africa" theory and the "multi-regional" theory (Cavalli-Sforza et al. 1994; Cavalli-Sforza et al. 1988; Excoffier et al. 1987; Swisher et al. 1996; Waddle 1994).

Much paleontological and archeological evidence indicates that anatomically modern humans originated in Africa, possibly in the sub-Saharan region (Brauer 1984; Protsch 1975; Swisher et al. 1996; Waddle 1994). Recent genetic evidence also seems to support this theory (Armour et al. 1996; Cann et al. 1987; Cavalli-Sforza et al. 1994; Cavalli-Sforza et al. 1988; Chen et al. 1995; Fey et al. 1990; Graven et al. 1995; Wainscoat et al. 1986). The evolutionary significance of the sub-Saharan region has stimulated further scientific interest in the diversity and genetic relationships of existing human populations there.