HIV-1 protease sequences are heterogeneous. Nucleotide sequences from protease quasispecies in peripheral blood mononuclear cells from infected children and adults were analyzed by constructing a phylogenetic tree. Major branches are black; colored branches represent sequences within individuals; individuals infected by related viruses are represented by shades of similar colors on a major branch. Inf1 and Inf2 are two unrelated individuals whose closely related virus sequences suggest that individual 2 was infected by individual 1.
Dunn et al. Genome Biology 2002 3:reviews3006.1-reviews3006.7 doi:10.1186/gb-2002-3-4-reviews3006