Field Science Center, Graduate School of Agricultural Science, Tohoku University
Abstract
In order to estimate the isozyme marker genes in Shijimi clam, Corbicula japonica, starch gel electrophoresis was carried out about 27 enzymes for three tissues. As a result, twelve isozyme loci, Aat-1, Aat-2, Ak-2, Fdp, Gpi, Idh-1, Mdh-1, Mdh-2, Mdh-3, 6Pgd, Sod-1 and Sod-2 coding for eight enzymes were estimated as genetic markers. Tissue specific patterns were not observed, but foot tissue was better used for isozyme analysis based on clarity of bands. Using the above marker genes, genetic variability was calculated as follows: the proportion of polymorphic loci ranged from 0.17 to 0.42 with a mean of 0.31, expected average heterozygosity was ranged from 0.041 to 0.103 with a mean of 0.071, and mean number of alleles per locus ranged from 1.8 to 2.0 with a mean of 1.9. The results revealed that genetic variability in Corbicula japonica was higher than fishes, crustacean and squids, but lower than the average of marine mollusks. These isozymes could be useful genetic markers for analyzing population structure of this species
