Northern Long-eared Bat (Myotis septentrionalis). Photo credit: Copyright The Smithsonian Book of North American Mammals, edited by Don E. Wilson & Sue Ruff, 1999. All rights reserved.

Field studies in wildlife toxicology often rely on the analysis of contaminant levels in wildlife tissues. Although this provides information on an animal’s exposure and the accumulated pollutant levels, it does not explicitly identify whether the contaminant has had toxic effects. Monitoring biochemical or molecular responses can provide additional information on the effects of contaminants in exposed wildlife. We are using damage to mitochondrial DNA (mtDNA) as one indicator of toxicity at the genetic level. mtDNA is particularly vulnerable to damage by contaminants that induce oxidative stress and this damage has shown to cause numerous pathological conditions in various organisms. In our studies, we are analyzing mtDNA damage by quantitative real-time PCR in non-destructively collected tissue samples from birds, bats, and turtles exposed to mercury and lead. The main goal of these projects is to test this non-destructive biomarker of genetic damage and relate it to other indicators of injury in the animals including contaminant levels, health, and reproductive success.

For more information contact Natalie K. Karouna-Renier, Patuxent Wildlife Research Center