Codominance of visual pigments in hybrid fishes

Visual pigments of lake char and brook char (Salmonidae) are based on two different proteins. Both proteins are present in first-generation hybrids between these species and they segregate in second-generation and backcross hybrids, as expected of a single-factor difference. This first genetic study suggests that shifts observed in the absorption spectra maxima of visual pigments are related to substitutions of amino acids in the visual proteins.