MITOCHONDRIAL GENETIC-VARIATION IN EUROPEAN, AFRICAN AND INDIAN CATTLE POPULATIONS

Mitochondrial DNA from representative animals of 13 different cattle b reeds was assayed for restriction fragment length polymorphisms (RFLP) to determine phylogenetic relationships and levels of variation among breeds; 16 different mitotypes were found, described by 20 poly morph isms. Within these 16 mitotypes two major lineages were apparent: an A fro-European and an Asian type. These were found to differ at over 2.3 % of sites surveyed. None of the mitotypes found in the Asian lineage was detectable in the Afro-European lineage and vice versa. Within ea ch of the major mitotypes there were no further significant difference s within or among breeds. Using rates of mitochondrial evolution estim ated from other species, the two lineages were estimated to have diver ged between 575 000 and 1 150 000 years ago; well outside the 10 000 y ears bp timeframe postulated by a single domestication hypothesis. The results presented are concordant with those generated in other studie s and provide strong evidence for an independent domestication of Asia n Bos indicus. Furthermore, the grouping of all African indicine popul ations within the clade containing all Bos taurus lineages points to t he hybrid origins of the humped cattle of that continent.