Isolation, DNA sequence and evolution of a color visual pigment gene of the blind cave fish Astyanax fasciatus.

Visual pigment genes have been isolated from a Mexican blind cave fish, Astyanax fasciatus. We report here the DNA sequence of one of these genes, which has 70% nucleotide similarity with both the human red and green pigment genes. This gene appears capable of encoding a functional protein and is probably responsible for the green-sensitive pigment found in the pineal organ of the blind cave fish (Tabata, 1982). The pattern of nucleotide substitutions most likely reflects functional adaptation of the visual pigment gene during the past 400 million years of fish evolution.