Figure 2: Random-amplified PCR of genomic DNA of two different snail strains (resistant and susceptible) of Biomphalaria alexandrina with arbitrary primer OPC-11 (5′-AAAGCTGCGG-3′). Lane 1: 100 bp DNA ladder, lanes 2–7; individuals of resistant snails, and lanes 8–13: individuals of susceptible B. alexandrina. The lanes from 1 to 13 were on the same gel run, and the space between the marker and lane 2 was wide, so it was cut and the lanes were spliced.