INTRODUCTION:

Chronic exposure to toxic levels of elements such as arsenic, cadmium, lead, mercury, nickel and others trace elements might cause abnormalities in gene expression affecting metabolic pathways such as those related to trace elements detoxification and the reproductive ability of animals. Rodent species have been the subject of several studies examining the physiological consequences of exposure to toxic levels of arsenic, cadmium and nickel, and how those elements affect their epigenetic mechanisms such as DNA methylation. Results from those studies can be used as an approach of the effects that can potentially occur on small mammals found in sites altered by geochemical or anthropogenic activities (e. g. mining, industrial waste).

METHODS:

An exhaustive literature review was conducted aimed to gain a better understanding of epigenetics, identifying mechanisms involved in the toxicity of trace elements, elucidating the effect of those trace metals in the epigenetics of genes involved in detoxification mechanisms and, finally, determining whether damages caused by exposition to high levels of trace elements are equally evident on any tissue from the same organism.

RESULTS AND DISCUSSION:

Pollutants can influence methylation of DNA patterns, but not all of them follow the same pathway. This varies widely among groups of trace elements or organic compounds. In addition to concentration and time of exposure, a number of other factors affect the toxicity pathway, including age, sex, food sources and, especially, the physiology of the species. Even within the same organism, the methylation patterns associated to a given element vary between tissues. Therefore, selecting the most appropriate tissue for discerning the animal´s actual condition is key when assessing the actual health status of wildlife species. Further studies are needed to better characterize the interactions between DNA methylation and trace elements, and elucidate potential mechanisms or interventions that can help to reduce their effects on wildlife health.