FIG. 2.

Competitive PCRs for 4-week aspen chip samples comparing the detectable cbh1 transcripts. The gene-specific PCR primers used are shown in Fig. 1 and Table 1. PCR mixtures contained the amounts of the competitive templates indicated below the gels in picograms of plasmid. As described previously (17), the levels of transcripts in samples were based on estimated equivalence points between competitive product and target cDNAs. The sizes of PCR products in base pairs are indicated on the left. Ethidium bromide-stained gels were photographed with a Foto/Analyst Visionary system (Fotodyne, Hartland, Wis.) and then scanned with a Microtek ScanMaker III and Adobe Photoshop 3.0.