Primate Colour vision

Researchers have found a link to our past by looking into the secrets behind our sight.  Humans use three different receptors in our eyes which detect different wavelengths of light.  The use of three such cells in our eyes is called trichromacy.  Some animals have four visual pigments but most animals including most mammals have two, or occasionally even only one.  What makes this especially interesting is that trichromacy is extremely rare in the animal world.  By investigating which primates have three visual pigments we get anouther window into the evolution of both our species and of the other primates.

What is especially interesting is that there is a defining split in the genetics of vision between old and new world primates.  New world primates include squirril monkeys, spider monkeys, howler monkeys and tamarins while new world primates include the great apes, gibbons and mandrills.  New world primates have the ability to be trichromatic but can be dichromatic.  This is because of an unusual method of random selection where the X chromosome only contains one of several possible genes, leaving males dichromatic and females with a chance of having both genes the same resulting in the same.

Cameron Etches 41418466

More info

http://www.sciam.com/article.cfm?id=evolution-of-primate-color-vision