THE GENETIC DRIFT OF HUMAN PAPILLOMAVIRUS TYPE-16 IS A MEANS OF RECONSTRUCTING PREHISTORIC VIRAL SPREAD AND THE MOVEMENT OF ANCIENT HUMAN-POPULATIONS

We have investigated the diversity of a hypervariable segment of the h uman papillomavirus type 16 (HPV-16) genome among 301 virus isolates t hat were collected from 25 different ethnic groups and geographic loca tions. Altogether, we distinguished 48 different variants that had div ersified from one another along five phylogenetic branches. Variants f rom two of these branches were nearly completely confined to Africa. V ariants from a third branch were the only variants identified in Europ eans but occurred at lower frequency in all other ethnic groups. A fou rth branch was specific for Japanese and Chinese isolates. A small fra ction of all isolates from Asia and from indigenous as well as immigra nt populations in the Americas formed a fifth branch. Important patter ns of HPV-16 phylogeny suggested coevolution of the virus with people of the three major human races, namely, Africans, Caucasians, and East Asians. But several minor patterns are indicative of smaller bottlene cks of viral evolution and spread, which may correlate with the migrat ion of ethnic groups in prehistoric times. The colonization of the Ame ricas by Europeans and Africans is reflected in the composition of the ir HPV-16 variants. We discuss arguments that today's HPV-16 genomes r epresent a degree of diversity that evolved over a large time span, pr obably exceeding 200,000 years, from a precursor genome that may have originated in Africa. The identification of molecular variants is a po werful epidemiological and phylogenetic tool for revealing the ancient spread of papillomaviruses, whose trace through the world has not yet been completely lost.