Genetic Variation in the Pacific Oyster, Crassostrea gigas

Abstract

Genetic variation, exhibited by electrophoretic analysis of tissue proteins and enzymes, of the Pacific oyster (Crassostrea gigas) was analyzed. Eleven systems were examined, reflecting 15 loci of which 8 were polymorphic and 7 were monomorphic. The number of alleles per locus varied from 1 at four loci (Aat-1, Mdh-1, Me, and To-1) without allelic variation, to 6 at the Pgm locus. The average number of alleles per locus was 2.7, while the effective number of alleles was calculated to be 1.3. An individual was found to be heterozygous, on the average, at 21% of the loci. Allelic variation was found at 11 out of 15, or 73% of the loci. At 53% of the loci the frequency of the most common allele was no greater than 0.95.