Maximum likelihood phylogenetic analysis of HIV-1 variants was based on Env V3-V5 coding region (454 nucleotides).
Tree was rooted by using the midpoint rooting method. The scale bar at the bottom indicates 7% nucleotide substitutions per site.
The asterisk along a branch represents the bootstrap value (significant statistical support) >70% and p<0.001 in the zero-branch-length test.