Genotypic analysis of Pol Unique Recombinant Forms (URFs): Boot scanning analysis of HIV-1 Pol gene with URFs. (A) isolate MBBL15; (B) isolate MBBL17; (C) isolate MBBL 24; (D) isolate MBBL18. The conditions used for this analysis were the following: Window: 400 bp, step size: 40 bp, gapstrip: on, reps: 100, Kimura (2-parameter), T/t.