Figure 2. Phylogenetic neighbor-joining tree of HIV pol sequences from infected subjects sampled in Banna from 2009 to 2011.

The sample sequences with ambiguous genotype were highlighted in blue and red, and labeled with numbers from 1 to 6 simultaneously. 1 and 2 indicated sequences can’t be well distinguished by this sequencing region, and were designated as B/CRF51_01B and C/CRF57_BC respectively. 3 to 6 indicated 16 clustered unique recombinant forms. Other sample sequences and reference sequences were showed in light brown and black respectively.