Fig. 1

Phylogenetic tree analysis based on the sequences of human immunodeficiency virus 1 pol gene. We constructed a phylogenetic tree based on the human immunodeficiency virus 1 pol gene sequences in the plasma samples of 1151 newly diagnosed individuals. CRF, circulating recombinant form; PI, protease inhibitor; NRTI, nucleoside reverse transcriptase inhibitor; NNRTI, non-nucleoside reverse transcriptase inhibitor