Provirus copy numbers. (A) The number of provirus copies per cell is shown for each provirus over time. Values were determined by qPCR of peripheral blood leukocyte DNA and are means with standard deviations (n = 3). Each panel represents results from one animal. Proviruses near proto-oncogenes, tumor suppressor genes, and genes unrelated to cancer are shown with circle, diamond, and square symbols, respectively. ND, not detected (<10–4 copies/cell). (B) Specific provirus copy numbers were determined by qPCR in the presence of increasing amounts of plasmid standards containing a different junction sequence. Samples analyzed were FD1 leukocyte DNA screened for the MECOM junction at 24 months and FD3 leukocyte DNA screened for the MTCP1 junction at 15 months, in the presence of the FD4-2 or FD1-4 junctions, respectively (see Table 2). Values shown are means with standard deviations (n = 3).