Fig. 2. Southern hybridization analysis confirming isolation of the DNA fragment producing the specific genomic polymorphism. Genomic DNA from soybean germplasms Essex (1), Faribault (2), Williams 82 (3), PI 209332 (4), and PI 437654 (5) digested with BamHI was hybridized with a PCR generated probe from an 8-kb BamHI fragment of a PI 437654 BAC clone associated with the Rhg4 resistance locus.