Figure 7. Expression of F3'5'H by reverse transcriptase–polymerase chain reaction (RT–PCR) in purple- and white-flowered plants. Ethidium bromide stained gel showing the RT–PCR amplified cDNAs from flower buds of three W1 locus isolines, L79-908 (W1,iⁱ,R,T,Wp), ‘Williams’ (w1,iⁱ,R,T,Wp), and L76-2023 (w1,iⁱ,R,t,Wp). The 1.6-kb amplified cDNAs shown in the (+) lanes are evidence that the two F3'5'H alleles in W1 and w1 lines are expressed at low levels in the flowers of these soybean lines. The (-) lanes are the result of parallel PCR reactions that were allowed in the absence of superscript to assess the extent of DNA contamination (negative controls).