Detection of heat stability variants in GPI isozymes of goldfish [Carassius auratus] and crucian carp [Cyprinus]

A combination of electrophoretic and heat denaturation techniques was used to identify the gene loci and alleles of the isozymes in goldfish and crucian carp Carassius auratus. Heat denaturation experiments revealed different heat stabilities among three loci (Gpi-1 super(*), Gpi-2 super(*), and Gpi-3 super(*)) encoding glucosephosphate isomerase (GPI) in goldfish and crucian carp. The heat stability differences were found in all the three loci examined. Cross experiments indicated that the observed differences among alleles at each locus in heat stability are controlled by a single incomplete dominant gene. Moreover, the heat stability alleles demonstrated a divergence in Gpi-1 super(*) and Gpi-2 super(*) loci between goldfish and crucian carp. The heat denaturation technique was thus useful for the revelation of hidden genetic variations of isozymes.