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Exposure to persistent organic pollutants and global DNA methylation in whales

Yoon Hee Cho, PhD., MPH, Associate Professor
SURP Student: 
Gabriela Martinez, University of Puerto Rico at Aguadilla

Environmental influences can result in physiological changes through epigenetics, which is the study of heritable changes in gene activity or function that is not associated with any change of the DNA sequence itself. Epigenetic modifications such as hypomethylation or hypermethylation have been shown to occur when exposed to persistent organic pollutants (POPs) which are known to disrupt the endocrine system. POPs are chemical substances that persist in the environment and pose a risk of causing adverse effects to human health and the environment. POPs work their way through the food chain by accumulating in the body fat of living organisms and becoming more concentrated as they move from one creature to another. When contaminants found in small amounts at the bottom of the food chain accumulate, they can pose a significant hazard to predators that feed at the top of the food chain. This means that even small releases of POPs can have significant impacts. In this project we worked with a method to estimate DNA methylation, referred to as Luminometric Methylation Assay (LUMA) and this method provides a way to analyze genome-wide DNA methylation in order to predict physiological and pathological conditions. We employed LUMA on DNA samples from the kidneys and gonads of marine mammals to determine their DNA methylation levels and find changes in methylation patters that might correlate with known persistent organic pollutants. After collecting and analyzing the data we didn’t see any significant association between DNA methylation levels and pollutant levels. After comparing these two tissues, there was no statistical difference between the studied tissues.