FIG. 3.

Quantitative analysis of control duplex PCR products from the human β-globin locus in MEL hybrids. Amplification products from 2 ng of wt-MEL genomic DNA following 27, 28, 29, and 30 cycles of duplex PCR with primer pair 5′δ1+3 in combination with huβPr3+4 (A), huβPr1+2 (B), HBG1+2 (C), and βIVS1+3 (D) are shown; each reaction was performed in duplicate. Quantitation of these products reveals that in each case, the total amounts of product (bars) increase linearly with cycle number and the product ratios (lines) do not vary significantly between identical reactions or as the cycle number increases. These results demonstrate that each primer is in the linear phase of amplification.