Figure 4.

Southern blot analysis of ApaI-digested genomic DNA (15 μg per lane) from 20 randomly selected progeny plants (lanes 1–20) from a Pro[s]1 × Pro[a/s]1 cross. Lanes marked with “I” or unmarked contained extracts from plants subsequently shown to be immune or susceptible to PVY infection, respectively. Lane M, M_r standard. The top portion of the filter was probed with a neomycin phosphotransferase (NPTII) sequence-specific probe to show transgene copy/locus number. The bottom portion was probed with an octopine synthase (OCS) terminator sequence-specific probe to show the presence or absence of Pro[s] and/or Pro[a/s] transgenes.