Serologically Defined Colon Cancer Antigen 8 (SDCCAG8)

OPN1LW encodes red cone pigment, one of 3 light-sensitive pigments that mediate human color vision. The red-sensitive and green-sensitive (OPN1MW) opsins comprise a family of repeated genes on the X chromosome. The red pigment gene and the multiple green pigment genes are arranged in a head-to-tail tandem array. The maximal sensitivity of red cones is 560 nm. The deduced amino acid sequences show 41% identity with rhodopsin. The red and green pigments show 96% mutual identity, but only 43% identity with the blue pigment. The autosomal one was clearly the blue cone pigment which is defective in tritan colorblindness; which of the other genes was for the red pigment and which for the green was resolved by study of males with red (protan) or green (deutan) colorblindness.