Blood polymorphism frequencies in the Sara Majingay of Chad.

Blood samples of 258 Sara Majingay of Ndila (Southern Chad) were analysed. Phenotype and allele frequencies are given for 22 polymorphisms. For each of these, the Majingay are compared to a number of other African populations. Then they are included in a set of 8 African populations between which multivariate distances for 25 alleles at 9 loci are computed. A two-dimensional representation is derived from the matrix of distances, and is discussed. It bears the stamp of gene flow in central Ethiopia, where an Arab admixture is evident, and in Southern Africa, where a reciprocal gene flow has marked the gene pools of Khoisan and Bantu speakers to a varying degree. The Majingay stand relatively near to the Bedik, another population of West-Central Africa. The non-Arab or non-Khoisan components of the gene pool of the other populations do not seem to differ largely from the gene pools of the West-Central African populations.