Verification of SIV DNA sequence retention in the gvpC gene following plasmid amplification. Following expansion of the pFM101D-SIV tat, rev and nef1 plasmid populations, DNA was tested for retention of the SIV specific insert carried by the recombinant gvpC genes. The agarose gel shows the PCR amplicon sizes of the selected SIV gene fragments and are indicated along the horizontal axis: tat:150, rev:243 and nef1:642 bp. Their presence inherently verifies SIV DNA retention by each r-gvpC genes. The Control (C) is an internal fragment from the gvpC gene and serves as a marker for the migration of this 350 bp fragment. The relevant primers are shown in Table 1.