Southern blot detection of vspB in R1 transgenic maize. Twenty micrograms of EcoRI restricted genomics DNA was electrophoresed through 0.8% agarose and blotted to Hybond membrane. The membrane was probed with digoxigenin labeled vspB. The alphabetical labels of each R1 family represent individual R1 plants. Control sample represent genomic DNA from untransformed maize Hi-II. Two positive control samples are also included: plasmid, pRSVP-1 restriction digested to liberate the vspB cDNA clone (only partial digestion occurred as evidenced by the two bands at higher molecular weight than the vspB fragment), and genomic DNA from the 45-1-2 R0 plant, previously shown to contain the vspB sequence. The Eco RI restricted soybean genomic DNA is also included as a positive control for hybridization of the soybean vspB probe.