INTERSPECIFIC VARIATIONS IN ADHESIVE PROTEIN SEQUENCES OF MYTILUS-EDULIS, MYTILUS-GALLOPROVINCIALIS, AND MYTILUS-TROSSULUS

Variation in the adhesive protein gene sequences of Mytilus edulis, M. galloprovincialis, and M. trossulus collected in Delaware, Kamaishi ( Japan), and Alaska, respectively, was analyzed by the polymerase chain reaction (PCR) using two sets of oligonucleotide primers. The first s et, Me 13 and Me 14, was designed to amplify the repetitive region. Th e length of the amplified fragments was highly variable, even among sa mples of the same species. Another set, Me 15 and Me 16, was designed to amplify a part of the nonrepetitive region. The length of the ampli fied fragments was uniform in each species and differed interspecifica lly; 180, 168 and 126 bp for M. edulis, M. trossulus, and M. galloprov incialis, respectively. The amplified sequence of M. trossulus resembl ed that of M. edulis. Mussels from other sites were also examined by P CR using Me 15 and Me 16. Wild mussels from Brittany (France) were ide ntified as M. edulis. Cultured mussels from the Mediterranean coast of France and wild mussels from Shimizu (Japan) were identified as M. ga lloprovincialis. Some wild mussels from Hiura (Japan) were identified as a hybrid between M. galloprovincialis and M. trossulus. Thus, the l ength of this part (variable region) of the sequence is proposed as a diagnostic marker for these three morphologically similar species and their hybrids.