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UW Scientists, Biotech Firm May Have Cure For Colorblindness
An anonymous reader writes with news about a possible cure for colorblindness. "For the more than 10million Americans with colorblindness, there's never been a treatment, let alone a cure, for the condition that leaves them unable to distinguish certain hues. Now, for the first time, two University of Washington professors have teamed with a California biotech firm to develop what they say may be a solution: a single shot in the eye that reveals the world in full color. Jay and Maureen Neitz, husband-and-wife scientists who have studied the vision disorder for years, have arranged an exclusive license agreement between UW and Avalanche Biotechnologies of Menlo Park. Together, they've found a new way to deliver genes that can replace missing color-producing proteins in certain cells, called cones, in the eyes."
I think you are mistaken -- 3 is normal. 2 is color blindness, commonly red/green blindness. And by receptors, I presume you mean cones.
Perhaps you are thinking of tetrachromat, where very few people have that 'condition', and Concetta Antico is one person who does... who also happens to be female... with the presumably prerequisite 2 X chromosomes. Eagles are also tetrachromat.
Not correct. Men and most women have three cones for color. Some of the genes for cones are on the X chromosome, so it can happen that a woman has a different gene for that cone on each of her two copies of the X chromosome. However, while many women therefore have four different cones (two of them almost identical), almost none who do demonstrate any heightened color sensitivity.
Many birds have four color receptors. Some have five.
Mammal eyes suck. Primates have about the best color perception of all mammals, and even the best is still pretty poor by bird standards.
It's not so cut and dried, actually. A lot of colour vision requires processing in the cortex so there isn't necessarily a clear cut relationship between the number of cone classes and an animal's colour acuity. A great example is the mantis shrimp which has a large number of different cone classes yet has crap colour vision. I don't know what bird colour acuity is or how it compares to our own, but don't assume it's necessarily better because they are tetrachromats. For instance, the wikipedia says that pigeons are pentachromats but they may not have access to the fifth channel. Many birds also have colour oil droplets in front of some photoreceptors in order to further tune their range. In effect, this may give them more than 4 cone classes.
soylentnews.org
> It's not so cut and dried, actually. A lot of colour vision requires processing in the cortex
I think you mis-spelled "retina" there. See if you can find a copy of http://www.scientificamerican.... from Jerry Lettvin, in 1986. I had the delight of attending several of teking Jerry's "General Physiology" course at MIT, which was filled with weird anecdotes and a profound scientific view of "how do things *really* work, and how did they get that way" with the evolutionary theory of ambulatory knishes avoiding predation by hungry students in Harvard Square.
Jerry's experiments with electrodes on individual visual neurons and work with other colleagues made very clear that much of vision is edge detection in the retina itself, which explains why that silly dress color illusion works so well. The cortex does not get raw color: it gets pre-processed information about "this region is much redder than that region, and far less blue and green compared to other regions, so it's definitely red". And I'm afraid it's also why the very silly "let's put grids of electrodes in the back of the eye" is never going to to work well. The electrodes are immersed in salty fluid, and the current spreads *much* too far: it recruits far too many of the pre-processing cells, and even putting a brilliantly designed electrode grid on the retina itself would skip all the subtle pre-processing in the retina and require much more complex pre-processing than visual researches like to even think about.