Scientific American says:

Analyses of primate visual pigments show that our color vision evolved in an unusual way and that the brain is more adaptable than generally thought.

The color vision of humans and some other primates differs from that of nonprimate mammals.

It is called trichromacy, because it depends on three types of light- activated pigments in the retina of the eye.

Analyses of the genes for those pigments give clues to how trichromacy evolved from the color vision of nonprimate mammals, which have only two kinds of photo pigments.

The authors created trichromatic mice by inserting a human pigment gene into the mouse genome. The experiment revealed unexpected plasticity in the mammalian brain.

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