Olfactory receptors vs. Cones for color

There are about 1,000 different odor receptor proteins and only three types of cones for color. Therefore, why do we not just see three different colors and smell a thousand odors?

It has been determined that almost 3% of all our genes are devoted to smell. Although humans have about 1000 odor receptors, only about 40% are usable. Each time a new odor is encountered, a combination of receptors are stimulated. As a result, an infinte number of smells can be recognized by the receptors.


While rods (for dark vision) only contain one type of photopigment, cones (for color vision) contain three types of photopigments. The cones are sensitive to three lengths of wavelength (short, medium and long), or blue, green and red.


recombinant technology may allow genetic transfer from one individual to another. In this way, genes from an individual who normally hears at a higher frequency may be transferred to an individual who is auditory impaired.

However, some ask whether this is an ethical practice. In my opinion, I do not think it would be ethical to provide gene technology to an individual to improve what was already normal. However, physiological changes brought about to allow a person to function normally are very welcome indeed!

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