Chemical-Induced Changes in the Genetic Structure of Populations: Effects on Allozymes

Abstract

Drawing from evidence on research in aquatic toxicology, we propose that allozyme analysis can be a useful tool for estimating the effects of environmental chemicals on genetic variation in natural populations. Recent research has associated exposure to environmental toxicants with changes in allozyme variation in populations of many species. Additionally, laboratory evidence has shown that variation in allozyme genotypes may either be adaptive to exposure to environmental toxicants or may be a marker for changes in genetic variation in response to environmental pollutants. Evidence is also presented to suggest that changes in allozyme variation are associated with significant changes in heterozygosity and polymorphism and that these changes may indicate an increase in susceptibility to negative impacts from further environmental perturbations. Because results from research studies are not equivocal, more effort is needed to test the ability of allozyme variation to reflect contaminant-induced changes in genetic variation in natural populations. However, the evidence presented here and elsewhere suggests that allozyme analysis may already be useful in estimating the impacts of environmental contaminants on genetic variation in natural populations.