Fig. 4. Southern hybridization analysis to determine GmSUB1 copy number in soybean. Genomic DNA from Williams 82 (1, 3, and 5) and PI 437654 (2, 4, and 6) digested with BamHI (1 and 2), DraI (3 and 4), and EcoRV (5 and 6) were hybridized with a GmSUB1 gene-specific probe (A). Differences in hybridization intensity with GmSUB1 probe were normalized to 26S rRNA content to determine differences in gene copy number (B).