For millennia anglers have wondered how fish see colors, and the rainbow of lures in every bait shop reveal that we're still guessing. But, in fish, reptiles and birds, that's all we can do for now, according to husband and wife vision researchers, Drs. Jay and Maureen Neitz at the Medical College of Wisconsin in Milwaukee.
"Primates and humans have three photoreceptors and can only see four basic colors, red, green, blue and yellow," says Jay Neitz, Ph.D. "Birds, fish and reptiles have four photoreceptors, allowing them to see things we cannot. They must see an entire dimension of color, including ultraviolet, infrared and all the combinations thereof, which we miss."
He is the R.D. and Linda Peters Professor in Ophthalmology at the Medical College. Maureen E. Neitz, Ph.D., is the Richard O. Schultz/Ruth Works Professor in Ophthalmology Research.
Two of the world's leading color vision researchers, the Neitzes are also pioneers in the field of functional genomics. Their studies of human color vision have not only identified the genes responsible for colorblindness, but also defined one of the first examples of a nervous system defect for which a person's DNA can predict both the occurrence and the severity of the disorder.
"This has been an important breakthrough, because as scientists strive to understand the genetic basis of human disease, more than merely revealing the presence of a genetic defect, it is also important to forecast the severity of the impairment," says Dr. Maureen Neitz.
They are currently studying gene therapy at the Froedtert & The Medical College of Wisconsin Eye Institute to evaluate the plasticity of the adult human visual system. Gene therapy has been demonstrated to correct deficits in the retina, but the major unanswered question is whether the brain can interpret new information it receives from the therapeutically-treated retina to restore vision. For humans to migrate around objects in their world requires that information about objects be transmitted from the retina to the brain, and that the brain recreate an image of the world.
Their color vision research has also provided them with unique opportunities to discover the steps in the causal chain from the gene, to protein function, to neural signal. They are applying these lessons to other genetic defects that cause visual impairment.
"We anticipate that our studies of the basic mechanisms controlling gene expression in the retina, and the structure/functional relationships among proteins involved in signal transduction, may lead to development of new methods for early diagnosis of retinal disorders, and ultimately extend our knowledge of the role genes play in construction of the nervous system," she says.
The Neitzes are currently conducting several research studies involving human subjects including a study of color vision and a study of how eye growth is controlled to cause nearsightedness. To learn more about these studies, interested participants can call (414) 456 2056.
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