Molecular characterization of the red visual pigment gene of the American chameleon (Anolis carolinensis)

The red sensitive visual pigment of the American chameleon, Anolis carolinensis, is unique in having absorption maximum some 50 nm further into the red than any other terrestrial vertebrate examined. We report here the isolation and sequence determination of the genomic DNA clone for the Anolis red visual pigment gene. Phylogenetic analysis shows that this gene is most closely related to the gecko green and chicken red visual pigment genes. We identified nine Anolis-specific amino acid replacements, seven of which reside in transmembrane domains and might contribute to the red-shift of the Anolis visual pigments.