Application of bioindicators for assessment of heavy metals' genetic and epigenetic effects in different regions of Armenia

Assessment of genetic and epigenetic effects of environmental pollutants in natural species is essential for estimation of risk to public health. Combination of comet assay, which is highly used for monitoring of environment genotoxicity in fish (Carassius auratus gibelio), crayfish (Astacus leptodactylus), lizards (bisexual Darevskia raddei and parthenogenetic Darevskia armeniaca) and field mouse (Apodemus uralensis) sampled in different locations of Armenia and Artsakh (Lesser Caucasus) and chemical analysis of water and soil was applied for assessment of genetic effects of environmental heavy metals. Also, for Darevskia lizards global DNA methylation analysis was performed for assessment of epigenetic effects, and the role of gender and age in response to environmental pollutants was studied. The obtained results showed intersite differences in DNA damage as well as a direct relationship between the levels of DNA damage and heavy metals in corresponding locations for all bioindicator organisms. While, levels of global DNA methylation in D. raddei and D. armeniaca from contaminated areas were significantly lower compared to reference sites, and a negative correlation was observed between global DNA methylation and heavy metal content. The levels of comets and global DNA methylation did not depend on sex but decreased with age of lizards. D. armeniaca showed a higher sensitivity toward environmental pollution than D. raddei in their common habitat. To summarize, all applied wide range animals could be sensitive bioindicators of heavy metal pollution of water and soil. DNA damage and global DNA methylation are valuable biomarkers for assessing the genetic/epigenetic effects of environmental pollutants.