1KPX595614539ENSG00000102076ENSMUSG00000031394P04000O35599NM_020061NM_008106NP_064445NP_032132OPN1LW is a gene on the X chromosome that encodes for long wave sensitive (LWS) opsin, or red cone photopigment.

[8] The protein encoded is a G-protein coupled receptor with embedded 11-cis-retinal, whose light excitation causes a cis-trans conformational change that begins the process of chemical signalling to the brain.

[7] Amino acid dimorphisms on exon 5 at positions 277 and 285 are the most influential on the spectral differences observed between LWS and MWS pigments.

[7] The LWS type I opsin is a G-protein coupled receptor (GPCR) protein with embedded 11-cis retinal.

[9] This shift is what begins the chemical reaction sequence responsible for getting the LWS cone signal to the brain.

[9] This excitation causes a conformational change in the protein and triggers a series of chemical reactions.

[9] Before humans evolved to be a trichromatic species, our vision was dichromatic and consisted of only the OPN1LW and OPN1SW genes.

[7] OPN1LW is thought to have undergone a duplication event that lead to an extra copy of the gene, which then evolved independently to become OPN1MW.

[10] The presence of both LSW and MSW opsins improves colour recognition time, memorization for coloured objects, and distance-dependent discrimination, giving trichromatic organisms an evolutionary advantage over dichromatic organisms when searching for nutrient-rich food sources.

[8] The severity of vision loss in a red-green colourblind individual is influenced by the Ser180Ala polymorphism.

[7] Affected individuals have dichromatic vision, with the inability to fully differentiate between green, yellow, and red colour.

[8] With this visual impairment, the individual can only see colours in the spectrum for SWS opsins, which fall in the blue range of light.