Molecular cloning and phylogenetic analysis of human immunodeficiency virus type 1 subtype C: a set of 23 full-length clones from Botswana

To better understand the virological aspect of the expanding AIDS epidemic in southern Africa, a set of 23 near-full-length clones of human immunodefi ciency virus type 1 (HIV-1) representing eight AIDS patients from Botswana were sequenced and analyzed phylogenetically. All study viruses from Botswa na belonged to HIV-1 subtype C. The interpatient diversity of the clones fr om Botswana was higher than among full-length isolates of subtype B or amon g a set of full-length HIV-1 genomes of subtype C from India (mean value of 9.1% versus 6.5 and 4.3%, respectively; P < 0.0001 for both comparisons). Similar results were observed in all genes across the entire viral genome. We suggest that the high level of HIV-1 diversity might be a typical featur e of the sub type C epidemic in southern Africa. The reason or reasons for this diversity are unclear, but may include an altered replication efficien cy of HIV-1 subtype C and/or the multiple introduction of different subtype C viruses.