RAPD profiles of Littorina striata, using the (a) OPG08 and (b) OPH12 primers of the Operon kits H and G (Operon Technologies). [ White arrow represents first locus, respectively OPG08-1 in (a) and OPH12-1 in (b); white and black arrows represent remaining loci in numerical order, respectively OPG08-2 in (a) and OPH12-2, OPH12-3 and OPH12-4 in (b); left lane represents a kb DNA ladder in both (a) and (b) ] .