In Behavior Genetics: Rhodopsin Gene Polymorphism Associated with Divergent Light Environments in Atlantic Cod
Christophe Pampoulie, Sigurlaug Skirnisdottir, Bastiaan Star, Sissel Jentoft, Ingibjörg G. Jónsdóttir, Einar Hjörleifsson, Vilhjálmur Thorsteinsson, Ólafur K. Pálsson, Paul R. Berg, Øivind Andersen, Steinunn Magnusdottir, Sarah J. Helyar and Anna K. Daníelsdóttir
The spectral sensitivity of visual pigments in vertebrate eyes is optimized for specific light conditions. One of such pigments, rhodopsin (RH1), mediates dimlight vision. Amino acid replacements at tuning sites may alter spectral sensitivity, providing a mechanism to adapt to ambient light conditions and depth of habitat in fish. Here we present a first investigation of RH1 gene polymorphism among two ecotypes of Atlantic cod in Icelandic waters, which experience divergent light environments throughout the year due to alternative foraging behaviour. We identi- fied one synonymous single nucleotide polymorphism (SNP) in the RH1 protein coding region and one in the 3’ untranslated region (3'-UTR) that are strongly divergent between these two ecotypes. Moreover, these polymorphisms coincided with the well-known panthophysin (Pan I) polymorphism that differentiates coastal and frontal (migratory) populations of Atlantic cod. While the RH1 SNPs do not provide direct inference for a specific molecular mechanism, their association with this dimsensitive pigment indicates the involvement of the visual system in local adaptation of Atlantic cod.