Replication of the human immunodeficiency virus type 1 (HIV-1) is associated with a high degree of viral sequence variation (1) that has been shown to correlate with disease state (2–8). The genetic diversity of the viral swarm within an HIV-1 infected individual is so extensive that this entity has been termed as quasi-species. Geographic distributions of HIV-1 reveal sequence clustering into a major group M and a minor (outlier) group O. Group M HIV-Is are further divided into a growing number of subtypes (A through H at this writing). Although DNA sequence analysis is the gold standard technique for HIV-1 genetic subtyping, molecular hybridization of untyped viral sequences with subtype-specific probes is frequently used as a subtyping screen.