Allozyme genotype and time to death of mosquitofish,Gambusia affinis(baird and girard), during acute exposure to inorganic mercury

Genetic plasticity in a mosquitofish (Gambusia affinis Baird and Girard) population was examined relative to acute mercury toxicity. Genotypes at eight loci (isocitrate dehydrogenase-1 and -2, mannosephosphate isomerase, glucosephosphate isomerase-2, fumarate hydratase, malate dehydrogenase-1, leucylglycylglycine peptidase and phenylalanylproline peptidase) were scored using starch gel electrophoresis. Two null hypotheses were tested: (a) time to death does not differ between genotypes at individual loci and (b) time to death does not differ with multiple-locus heterozygosity. Genotypes at three of the eight loci displayed significant effects on mosquitofish time to death. Multiple-locus heterozygosity also had a significant effect on time to death. Significant amounts of genetic plasticity were found in a population of mosquitofish with no previous exposure to inorganic mercury.