Influence of the background RNA the on detection of EGFP and GNPDA cDNAs. The high-abundance EGFP results were reported as 1 fg equivalent (i.e. divided by 1,000), whereas low-abundance EGFP results were uncorrected. Quantities of cDNA copies detected for GNPDA in total RNA (Table 2 and 3) were corrected for the amount of background RNA. Data for the SuperScript II, SuperScript III, Sensiscript, and PowerScript systems (panels A, B, C, and D, respectively) were plotted using the same scale for comparison purposes.