Saturday, March 24, 2007

Genetic Studies Endow Mice With New Color Vision

Although mice, like most mammals, typically view the world with a limited color palette – similar to what some people with red-green color blindness see – scientists have now transformed their vision by introducing a single human gene into a mouse chromosome. The human gene codes for a light sensor that mice do not normally possess, and its insertion allowed the mice to distinguish colors as never before.

The new abilities of the genetically engineered mice indicate that the mammalian brain possesses a flexibility that permits a nearly instantaneous upgrade in the complexity of color vision, say the study’s senior authors, Gerald Jacobs and Jeremy Nathans.

Trichromacy is dependent on three types of photoreceptor cells in the retina that preferentially absorb lights at different wavelengths. These are known as cone cells and each type contains a particular kind of light-absorbing sensor protein. Short-wavelength-sensitive (S) cone cells are most sensitive to blue lights, medium-wavelength-sensitive (M) cone cells are most sensitive to green lights, and long-wavelength-sensitive (L) cones are most sensitive to red lights. When light strikes the retina and activates the cone cells, the brain compares the responses of the S, M, and L photoreceptors, and it is the brain’s assessment of their relative levels of activation that we perceive as color.

Most mammals, including mice, are dichromats, possessing only S and M cone pigments. As a consequence, they can distinguish only a fraction of the wavelengths that can be distinguished by humans.
I while back I was reading an article about how eye sight works in various animals and found it fascinating. I hadn't realized that birds have much better color eyesight than humans. Instead of being dichromats or trichromats, they are actually tetrachromats having 4 different photoreceptor cells. And beyond seeing just "visible" light, they also can see in the ultraviolet spectrum. Some women actually are tetrachromats as well. Although they can't see ultraviolet light, they see more distinct colors when looking at a rainbow.

If this experiment is a success, I say lets start making tetrachromat humans. And lets give them the ability to see in the UV range like birds. My only concern is I am not sure what this would do to viewing TVs and computer monitors. They simulate all colors by using just red, green and blue light. I don't know if this would goof up the way we view TV as it might take a different blend of red, green and blue (and maybe a new UV frequency of light) to create the appearance of yellow or purple for our new eyes.

via physorg


crush41 said...

This is the beginning of something as monumental as the Industrial Revolution, the ICE, or the world wide web. We are on the brink of a revolution.

Fat Knowledge said...

I certainly hope so. Unfortunately, medical advances seem to come much slower than other technological advances, because you have to be much more careful that you aren't negatively impacting your test subjects.

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