Papio cynocephalus endogenous retrovirus among old world monkeys: Evidencefor coevolution and ancient cross-species transmissions

To study the evolutionary history of Papio cynocephalus endogenous retrovir us (PcEV), we analyzed the distribution and genetic characteristics of PcEV among 17 different species of primates. The viral pol-env and long termina l repeat and untranslated region (LTR-UTR) sequences could be recovered fro m all Old World species of the papionin tribe, which includes baboons, maca ques, geladas, and mangabeys, but net from the New World monkeys and homino ids we tested. The Old World genera Cercopithecus and Miopithecus hosted ei ther a PcEV: variant with an incomplete genome or a virus with substantial mismatches in the LTR-UTR. A complete PcEV was found in the genome of Colob us guereza-but not in Colobus badius-with a copy number of 44 to 61 per dip loid genome, comparable to that seen in papionins, and dth a sequence most closely related to a virus of the papionin tribe. Analysis of evolutionary distances among PcEV sequences far synonymous and nonsynonymous sites indic ated that purifying selection was operational during PcEV evolution, Phylog enetic analysis suggested that possibly two subtypes of PcEV entered the ge rm line of a common ancestor of the papionins and subsequently coevolved wi th their hosts. One strain of PcEV was apparently transmitted from a papion in ancestor to an ancestor of the central African lowland C. guereza.