Viral interpatient diversity of the RT-coding region in the gut tissues (esophagus (E), stomach (S), duodenum (D), colon (C)) and PBL (L) of HIV-1 infected patients at different visits. Viral RT-coding sequences tended to a more conserved sequence among patients in the esophagus, stomach, duodenum and PBL, as reflected by the lower mean total distance (d) between patients, while the sequences in the colon became more diverse over time. Similarly, the decrease in mean total non-synonomous distance (dN, i.e. amino acid changing mutations) for PBL and duodenum suggested evolution towards more conserved RT protein sequences over time among patients, while the increased dN reflected the RT protein sequence becoming more diverse over time in the colon among patients. These observations indicated that the RT-coding region evolved differently in the different gut tissues and PBL in this group of patients. (* p < 0.05, Dunnett C post-hoc analysis)