Meeting Abstract

35.4  Monday, Jan. 5  Light environment limits gene expression in rapidly evolving cichlid radiations HOFMANN, C.M.**; SEEHAUSEN, O.; CARLETON, K.L.; University of Maryland chofma1@umd.edu

Sensory adaptation to the light environment has been repeatedly demonstrated in opsin genes. However, recent work suggests that changes in gene expression may also play a large part in tuning visual sensitivity. Cichlids have seven different cone opsin genes, with different species expressing different subsets of opsins, making them an ideal system for investigating adaptive gene expression. We examined how gene expression differed in two independent cichlid radiations that differ in their global light environment. Lake Malawi has some of the clearest water on the planet, which results in a relatively blue-green light environment, while shallower Lake Victoria has more turbid water, and thus a red-shifted light environment. We found large differences in the sets of opsins that cichlids in these two lakes expressed. Two opsins, the UV and the RH2B (blue green), were not expressed in any of the Lake Victoria species we examined and all Lake Victoria cichlids expressed LWS opsin. Thus, Lake Victoria cichlids only express a longer-wavelength shifted subset of the opsins that are expressed in Lake Malawi. Furthermore, we examined species with a variety of life histories and foraging modes, suggesting that the light environment may override other ecological factors, such as foraging mode in rapidly evolving radiations.