Meeting Abstract
Epigenetic mechanisms can change gene expression and phenotypes in response to environmental stress. Power plant-cooling lakes emblemize anthropogenic temperature changes and two lakes in Illinois exhibit characteristics essential to studying temperature induced phenotypic changes. We compared populations of Bluegill sunfish in the power plant-cooling Lake Coffeen which is 2-6 ºC warmer to populations in the nearby ambient Lake Mattoon. Bluegill in the thermally-elevated lake have a shorter lifespan, show a decrease in growth performance, and population structure is skewed towards younger fish. We performed MS-AFLP to determine if DNA methylation differed between fish from the thermally-elevated and ambient lake. We identified significant epigenetic differentiation between specimens from both lakes and we identified five loci with increased, and two loci with decreased DNA methylation among individuals in the thermally-elevated lake compared to the ambient lake. Further, our results show differentiation in the frequency of methylation among sites between lakes, while sites within the thermally challenged lake did not differ. These results suggest that DNA methylation is an important mechanism contributing to the observed phenotypic variation in Bluegill from thermally-elevated lakes compared to ambient lakes. We then used epiRADseq to generate 185,166 fragments to compare broad scale genomic differences in DNA methylation among fish from Lake Coffeen, Lake Mattoon, and Bluegill collected in Puerto Rico, which serve as a geographically disjunct group with higher ambient temperatures. We will compare results between MS-AFLP and epiRADseq.
