Strategies for mitigating anthropogenic stressor effects on wildlife are limited by difficulties in linking mechanistic causation to broad consequences for populations. Epigenetics, or the interaction between the environment and gene expression, postulates that chemical modifications to DNA can regulate changes in gene expression that become heritable. The ability to quantify the extent of such changes in DNA chemistry presents a novel biomarker for monitoring the rapid responses of wildlife to anthropogenic stressors under a genotoxicological framework. Using a conserved epigenetic marker in vertebrates, we sequence the extent of methylation of genome-wide cytosines from two native fish species recruited from a spawning reef impacted by mining wastes. Our aim is to investigate the relationships between mine tailing exposure with changes in DNA methylation and subsequent gene expression that are representative of adverse developmental or toxicological stress in exposed fish.
Results/Conclusions
Whole genome DNA extractions following reduced representation bisulfite sequencing methods have been completed from eggs harvested from female Lake Trout (Salvelinus namaycush) and Whitefish (Coregonus clupeaformis) returning to spawn at Buffalo Reef, Lake Superior in addition to samples collected from population outgroups. These genomes are being screened for changes in DNA methylation patterns in the Buffalo Reef spawning females relative to the outgroup samples. We predict a higher degree of DNA methylation among lake trout and whitefish eggs spawned on the reef compared to the outgroups. In addition, this research is contrasting DNA methylation patterns among lake trout and whitefish eggs reared across a gradient of mine tailing exposures under controlled experimental conditions. Remediation efforts at Buffalo Reef require an understanding of the relationship between mine tailing coverage of the reef and acute or chronic toxicity effects. We predict that this epigenetics approach will demonstrate the subtle chronic toxicity effects of mine tailings at nominal exposure levels, and also demonstrate the applicability of epigenetics toward investigating species’ responses to disturbances in a changing global ecosystem.
