Biochemical studies on the expression of overdominance at the phosphoglucomutase-2 locus in the Pacific oyster, Crassostrea gigas (Thunberg) ...

• Main Author: Pogson, Grant H.
• Format: Text
• Language: English
• Published: University of British Columbia 2010
• Subjects: Crassostrea gigas; Pacific oyster
• Online Access: https://dx.doi.org/10.14288/1.0098360; https://doi.library.ubc.ca/10.14288/1.0098360

Numerous studies have documented significant associations between multiple-locus heterozygosity and fitness-related traits in natural populations, but the explanations for these patterns remain unknown. The objective of the present study was to examine the merits of the overdominance hypothesis as the mechanism responsible for a positive correlation between adult body weight and heterozygosity involving the phosphoglucomutase-2 (Pgm-2) locus in the Pacific oyster, Crassostrea gigas. The kinetic and structural properties of seven Pgm-2 genotypes were examined over physiological ranges of temperature and pH. Significant differences were detected between Pgm-2 genotypes in a variety of enzymic parameters, but these were largely confined to genotypes possessing the Pgm-2-92 allele, and heterozygotes displayed strict intermediacy for all functional and structural properties examined. The expression of marginal overdominance at the Pgm-2 locus was considered unlikely because of the limited scope of the observed ...