Genetically Tweaked Mice Get Human-Like Vision

Scientists have some lab mice seeing red. The animals had their vision genetically upgraded and can now see colors normally invisible to rodents. The finding, detailed in the March 23 issue of the journal Science, has implications for the evolution of full-color, or “trichromatic,” vision in our own ancestors. “What we are now looking at in these mice is the same evolutionary event that happened in one of the distant ancestors of all primates,” said study team member Jeremy Nathans of Johns Hopkins University. Most mammals, mice included, have dichromatic vision. They see the world in shades of grey and a few other colors because they only have two types of light-sensitive molecules, called “photopigments,” in their eyes. A genetic mutation in primates 40 million years ago endowed our early ancestors with a third photopigment sensitive to red light, vastly expanding the color palettes of their eyes.