Red-opsin polymorphisms

So I'm writing a paper on non-visual transduction in retinal ganglion cells and came across something I've been told but never had a full appreciation for... until now!

Jeremy Nathans, who worked one floor below my lab in the Wilmer Eye Hospital when I was a wee-little freshman, was the first to isolate the three opsins responsible for color vision in 1989... red-, green-, and blue-opsin:

Since then, many functional polymorphisms for these genes have been identified, resulting in amino acid changes in protein structure. Take for example, the Ser180Ala common polymorphism in red-opsin. This residue is located in the alpha helix of the binding domain for opsin-retinal (retinal being the molecule responsible for firing) interactions, and the change from serine (polar) to alanine (nonpolar) causes the red absorption spectrum to SHIFT down. People with the alanine residue have a lower sensitivity to red light than do people with serine in the same position.

... But that's just one polymorphism. A quick search on PubMed finds 36 polymorphisms on red conopsin only, many of which are quite common! Imagine the possibilities... and that's just the visual system! The same applies for olfactory epithelial tissue!

!!!

Isn't it glamous?!