GENETIC DIVERSITY OF SIMIAN IMMUNODEFICIENCY VIRUSES FROM WEST-AFRICAN GREEN MONKEYS - EVIDENCE OF MULTIPLE GENOTYPES WITHIN POPULATIONS FROM THE SAME GEOGRAPHICAL LOCALE

High simian immunodeficiency virus (SIV) seroprevalence rates have bee n reported in the different African green monkey (AGM) subspecies. Gen etic diversity of these viruses far exceeds the diversity observed in the other lentivirus-infected human and nonhuman primates and is thoug ht to reflect ancient introduction of SN in the AGM population. We inv estigate here genetic diversity of SIVagm in wild-living AGM populatio ns from the same geographical locale (i.e., sympatric population) in S enegal. For 11 new strains, we PCR amplified and sequenced two regions of the genome spanning the first fat exon and part of the transmembra ne glycoprotein. Phylogenetic analysis of these sequences shows that v iruses found in sympatric populations cluster into distinct lineages, with at least two distinct genotypes in each troop. These data strongl y Suggest an ancient introduction of these divergent viruses in the AG M population.