|MadSci Network: Genetics|
Dear Marion, Thanks for your question about fruit flies. You've come to the right place for an answer. As a matter of fact, I am a scientist who studies fruit flies in a laboratory all day long. We study the development of the fruit fly's eye. More importantly, I study the development of pigment cells in the eye. That's right; the eye is made up of two different types of cells. There are cells that are sensistive to light and there are pigment cells that give the eye its distinctive color. Neither type of cell is much good without the other. There are actually two types of pigment in the eye of the fruit fly. The first kind is a rusty-colored pigment called ommachrome pigment. The second is the reddish pigment, called pteridine, which gives the eye its bright red color. These pigment molecules are not unlike the pigment that we have in our skin or our hair or our eyes, for that matter. Pigment molecules provide color to various tissues in the body. Why are pigment molecules important? The pigment in a fly's eye acts as insulation so that incoming rays of light are focused on the photoreceptor cells. The optical insulation prevents light rays from scattering when they enter the eye. The result is clearer vision for the fly. Finally, there are actually flies that have a mutation that inhibits the production of pigment in the eyes. These flies have white eyes, kind of like an albino animal that has no pigment in its skin. As scientists, we like to learn about mutations like that. Learning about mutations in fruit flies and other animals helps us to learn more about mutations in humans that can cause a variety of diseases.
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