The aye-ayes have it: The preservation of color vision in a creature of...( A quest to gain a more complete pict...),Health

A quest to gain a more complete picture of color vision evolution has led Biodesign Institute researcher Brian Verrelli to an up-close, genetic encounter with one of the worlds most rare and bizarre-looking primates.

Verrelli and his ASU team have performed the first sweeping study of color vision in the aye-aye (pronounced eye-eye), a bushy-tailed, Madagascar native primate with a unique combination of physical features including extremely large eyes and ears, and elongated fingers for reaching hard to access insects and other foods. Verrelli, lead author George Perry, and collaborator Robert Martins results, published in the journal Molecular Biology and Evolution, have led to some surprising conclusions on how this nocturnal primate may have retained color vision function.

Verrellis group focuses on color vision to better understand genetic variation between human and other primate populations and the truly big evolutionary questions as to what makes us human. At least within humans and some other primates, we know that there are three different genes responsible for color vision, said Verrelli. The genes, called opsins, come in three forms that shape our color vision palette, one for blue, another for green, and a third for red.

What makes that very interesting is that the green and red are found on the X chromosome [sex chromosome], and it is the manipulation of those two genes alone which is related to color blindness for eight to ten percent of the male population, explains Verrelli. In a 2004 study in the American Journal of Human Genetics by Verrelli and collaborator Sarah Tishkoff of the University of Maryland, they suggested that natural genetic selection has provided women with a frequent ability to better discriminate between colors than men.

These three genes may explain all the variation that we might see across human populations in color vision, said Verrelli. But how did our range of color vision variation come
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