Maximum clade credibility tree with time scale obtained with BEAST using 1,011 nucleotide sites of pol gene sequences (nucleotides 2,253–3,263 of HXB2 coordinates) from 56 HIV-1 subtype C isolates from Senegal. This tree is obtained using the relaxed uncorrelated lognormal molecular clock model and moderately informative substitution rate prior (Normal: 2.5×10−3,7.5×10−4). Clades with posterior probabilities ≥95% are indicated by diamonds. MSM isolates are colored in red.