Meeting Abstract
Populations of eastern oysters (Crassostrea virginica) in the Northern Gulf of Mexico will be challenged by predicted changes in environmental conditions associated with climate change. As environmental variation shifts, a combination of phenotypic plasticity and local adaptation will be important mechanisms that may allow one population to outperform another within a given estuary. Recent evidence suggests that there are population specific patterns in DNA methylation in C. virignica and that DNA methylation is significantly affected by changes in the environment. In this study we have explored changes in DNA methylation and gene expression between 2 populations of C. virginica collected from a high and a low salinity site along coastal Louisiana. Crosses within each population were conducted at Grand Isle Hatchery (LA) and the progeny were out-planted at either a medium-high salinity site (Grand Isle, LA; 21 psu) or at a low-salinity site (Chauvin, LA; 9 psu). To test for the effects of rearing environment and genotype we sampled 20 oysters for each population from each site after 1 year. We assessed changes in DNA methylation using reduced representation bisulfite sequencing (RRBS) and changes in gene expression using 3’TAG-sequencing. With this approach it was possible to genotype each individual in order to disentangle genetic from environmental drivers of both DNA methylation and transcriptome level plasticity. This analysis identified some variation in methylation and expression between families within a site – suggesting a genetic basis for the variation; and highlighted that the majority of plasticity was observed between common garden out-plant sites but within the low salinity population.
