Geographic distribution and frequency of a taurine Bos taurus and an indicine Bos indicus Y specific allele amongst sub-Saharan African cattle breeds

We report for the first time, and for the whole of sub-Saharan Africa, the geographical distribution and the frequency of an indicine and a taurine Y specific allele amongst African cattle breeds. A total of 984 males from 69 indigenous African populations from 22 countries were analysed at the micr osatellite locus INRA 124. The taurine allele is probably the oldest one on the continent. However, the taurine and the indicine alleles were present in 291 males (30%), and 693 males (70%), respectively. More particularly, 9 6% of zebu males (n = 470), 50% of taurine males (n = 263), 29% of sanga ma les (crossbreed Bos taurus x Bos indicus, n = 263) and 95% of zebu x sanga crossbred males (n = 56) had the indicine allele. The Borgou, a breed class ified as zebu x taurine cross showed only the zebu allele (n = 12). The ind icine allele dominates today in the Abyssinian region, a large part of the Lake Victoria region and the sahelian belt of West Africa. All the sanga ma les (n = 64) but only one from the Abyssinian region had the indicine allel e. The taurine allele is the commonest only among the sanga breeds of the s outhern African region and the trypanotolerant taurine breeds of West Afric a. In West Africa and in the southern Africa regions, zones of introgressio n were detected with breeds showing both Y chromosome alleles. Our data als o reveal a pattern of male zebu introgression in Mozambique and Zimbabwe, p robably originating from the Mozambique coast. The sanga cattle from the La ke Victoria region and the Kuri cattle of Lake Chad, cattle populations sur rounded by zebu breeds were, surprisingly, completely devoid of the indicin e allele. Human migration, phenotypic preferences by the pastoralists, adap tation to specific habitats and to specific diseases are the main factors e xplaining the present-day distribution of the alleles in sub-Saharan Africa .