Figure 1: Random-amplified PCR of genomic DNA of two different snail strains (resistant and susceptible) of Biomphalaria alexandrina with arbitrary primer OPB-18 (5′-CCACAGCAGT-3′). Lane 1: 100 bp DNA ladder and lanes 2–7: individual of resistant snails and lanes 8–13: individual of susceptible B. alexandrina. The lanes from 1 to 6 and from 8 to 13 were on the same gel run, but lane 7 was on a separate one.