Lack of genotype-by-environment interaction suggests limited potential for evolutionary changes in plasticity in the eastern oyster, Crassostrea virginica

Eastern oysters in the northern Gulf of Mexico are facing rapid environmental changes and can respond to this change via plasticity or evolution. Plasticity can act as an immediate buffer against environmental change, but by buffering the effects of selection it could impact the organism’s ability to evolve in subsequent generations. While plasticity and evolution are not mutually exclusive, the relative contribution and interaction between them remains unclear. In this study, we investigate the roles of plastic and evolved responses to environmental variation and Perkinsus marinus infection in Crassostrea virginica by using a common garden experiment with 80 oysters from 6 families outplanted at two field sites naturally differing in salinity. We use a combination of growth data, P. marinus infection intensities, and 3’ RNA sequencing (TagSeq) to identify the effect of genotype (G), environment (E), and genotype-by-environment interaction (GxE) on the oyster’s response to site. As one ...