Fig. 1. Structure of flavonoid 3'-hydroxylase gene in soybean near-isogenic line, To7B. The entire F3'H gene is covered by two genomic clones, F3'H-G1 and F3'H-G2. PCR primer positions are indicated by small arrows. Designation of the primers is shown to the left of each primer pair. Information of the primers is presented in Table 1. The F3'H gene consists of three exons and two introns.