MOLECULAR CHARACTERIZATION OF HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1 ISOLATES FROM VENEZUELA

Eight HIV-1 isolates from Venezuela have been characterized by nucleot ide sequencing of the entire reverse transcriptase (RT)- and surface g lycoprotein (gp 120)-coding regions, Average mutant frequencies were 2 .5 x 10(-2) substitutions per nucleotide (s/nt) for the RT-coding regi on, and 10 x 10(-2) or 6.8 x 10(-2) s/nt for the gp120-coding region, depending on whether gaps introduced for optimal alignment were or wer e not, respectively, considered in the calculations, Phylogenetic tree s were derived by maximum-likelihood, neighbor-joining, and maximum pa rsimony methods, In the trees derived from both RT- and gp120-coding r egions, Venezuelan isolates cluster with subtype B viruses, However, t he relative position of some of the isolates is considerably different in the two trees, Unique V3 loop amino acid sequences, not represente d in the current database, have been identified among the Venezuelan i solates, In addition to representing the first molecular characterizat ion of HIV-1 from Venezuela, the extensive genetic heterogeneity obser ved reinforces the interest in characterizing additional HIV-1 isolate s worldwide for adequate vaccine design.