FIG. 4.

PCR analysis of nascent strand abundance at the Sciara II/9A locus. Nascent DNA from amplification or preamplification stage Sciara salivary glands was fractionated by alkaline agarose gel electrophoresis. Small nascent DNA (N) of 860 to 900 bp (shown here) or 1,500 to 1,570 bp (data not shown) was mixed with increasing amounts of competitor DNA (C) (the number of competitor DNA molecules is indicated) and coamplified by PCR with primer sets A to E. The PCR products were resolved on a 4% MetaPhor agarose gel and stained with ethidium bromide, and the intensity of each band was quantified to allow calculation of the number of small nascent strand DNA molecules (n) per five salivary gland equivalents.