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Colored lights were used to show that the brains of genetically altered mice could efficiently process sensory information from new photoreceptors in their eyes. Here, a mouse deciding that the third colored panel looks different from the other two receives a drop of soy milk as a reward. For this set of three lights, only the soy milk dispenser over the third panel releases a drop of soy milk.

In a study published in the March 23, 2007, issue of the journal Science, Howard Hughes Medical Institute researchers at Johns Hopkins University School of Medicine, together with researchers at the University of California at Santa Barbara, demonstrated in a series of cleverly designed color vision tests that the genetic modification allows mice to see and distinguish among a broader spectrum of light waves. The experiments were designed to determine whether the brains of the genetically altered mice could efficiently process sensory information from the new photoreceptors in their eyes. Among mammals, this more complex type of color vision has only been observed in primates, and therefore the brains of mice did not need to evolve to make these discriminations.

http://www.hhmi.org/news/nathans20070323.html

Comments?

So mice can't usually discriminate among these colours? Interesting. I wonder how they would cope with bird vision? Some birds of prey can see in the UV spectrum, enabling them to see the urine left by their prey.

I'm just wondering, won't altering this evolutionary response have unexpected side effects? After-all nature would've given them color vision if they needed it, perhaps having it will interefere with some mechanism already in place?

darksidZz - "nature would've given them color vision if they needed it". IMO I'd avoid the anthropomorphising here, but yeah, if color vision would provide mice in the wild with an advantage, there is a good chance (though no gaurentee) that mice would have color vision by now (barring other forces that would pressure against that change).

However, mice tend to be nocturnal, and/or live in very low-light settings. In general, night vision is color-less or nearly color-less; the rods that detect low levels of light are not seperated into different versions for different wavelengths like cones are.

So it may very well be that mice don't have that ability because they didn't have a use for it - not that having it would be bad. It could also be that developing low-light, color sensitive structures just never came up; I don't know this question - did rodents break off of the mammelian tree before cones came into being? (I'll try and look this up later, but if anyone knows, please speak up).

All in all - these lab mice are not living in thier natural environments, so the concepts of "good" and "bad" are completely upended.

"Our inventions are wont to be pretty toys, which distract our attention from serious things. They are but improved means to an unimproved end,... We are in great haste to construct a magnetic telegraph from Maine to Texas; but Maine and Texas, it may be, have nothing important to communicate." - Henry David Thoreau