Amplicons produced using in-house HIV genotyping assays (see text). The positions of amplicons in HIV genotyping assays described in Table 1 are shown. Solid lines show the first-round PCR amplicons, and dotted lines show the amplicons produced in nested PCR. Three assays were used for analysis (#1, #2, and #3). Assay #2 produces four short, overlapping amplicons (#2-2, #2-3, #2-4, and #2-5). PRO, HIV protease; RT, HIV reverse transcriptase. Numbers above the diagram indicate coordinates in HXB2.