Functional characterization of a genetic polymorphism strongly associated with stress responsiveness in salmonid fishes.

This project aims at developing strategic bilateral collaboration with the group of Professor Patricia M. Hinkle, University of Rochester to carry out a specific pre-project on a recently discovered polymorphism affecting skin pigmentation and physiologic al responses to stress in salmonid fishes in aquaculture. In silico data modeling indicate that MC1R, with methionine at aa position 176 (M176), binds differently to MRAP compared to when leucine is present in the same position (L176). Based on this and a dditional experimental evidence we hypothesize that the M176 variant causes less MRAP/MC2R binding in ER, and thereby reduces the number of active MC2R receptors available for ACTH-binding, explaining the observed decrease in cortisol production in LR fis h. In the proposed pre-project we will be able to carry out a functional validation of this hypothesis, by conducting different cell-based experiments. In addition to the fundamental scientific interest in explaining this phenomenon, the results are impor tant for evaluating the potential of selection for reduced sensitivity to stress in aquaculture breeding programs.