The complete mitochondrial DNA (mtDNA) molecule of the baboon "Papio hamadryas" was sequenced and included in a molecular analysis of 24 complete mammalian mtDNAs. The aim of the study was to time the divergence between the Old World monkeys (Cercopithidae) and the Hominoidea. That divergence, at 30 million years ago (mya), was a reference point for the split between chimpanzee, and "Homo" at 5 mya. 