Electrophoretic study of gene-enzyme systems in oysters classified as Crassostrea gigas (Thunberg, 1793) and Crassostrea angulata (Lamarck, 1819) (Mollusca: Ostreidae)

As a further contribution to the systematics of species belonging to the genus Crassostrea, electrophoretic studies of gene-enzyme system have been carried out on five populations of oysters regarded as either Crassostrea gigas or Crassostrea angulata species. Two populations of C. gigas from Japan (Karakawa and Hiroshima), one of C. gigas from France (Fouras), one of C. angulata from Portugal (Sado) and one of Crassostrea sp. from Italy (Chioggia) have been examined. The electrophoretic study of 20 enzyme loci and the genetic distance value showed no significant genetic divergence among the Crassostrea sp. populations. Thus the results of this study seem to confirm and extend to other populations what obtained by Buroker et al. (1979), that is a remarkable genetical identity between the two species Crassostrea gigas and Crassostrea angulata.