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Can you make my blue eyes black?
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[QUOTE]Originally posted by meninarmer: [QB] [QUOTE]Originally posted by Knowledgeiskey718: [qb] Again, this shows you don't read, or don't understand what you read. [b]**In terms of eye color, OCA2 comes in two versions—brown (B) and blue (b). The brown version works in the stroma, while the blue version does not.**[/b] Since the blue version doesn’t work there, no melanin builds up. So these individuals end up having blue eyes. OCA2 isn’t just involved in eye color. When it is completely broken, you end up with something called P-gene related oculocutaneous albinism.(Which is what you're talking about) This is a form of albinism more common in Africans than in Europeans. [/qb][/QUOTE]^ I'd strongly suggest you read more. Melanin is produced in two versions, black and red. There is no "blue" pigment, only color mixes of the two primary melanin versions plus a third white base, light Your Doctor above is incorrect describing color gene balancing as a "on"/"off" switch in a digital sense. Rather, it is much more accurately described as a "Fuzzy" switch, where the gene may allow many active states between on and off. Therefore, each gene expression acts more like a flow valve, each being capable of being full open to full closed and many increments in between, more analog in nature than digital. See above chart, and you can relate each gene in the sequence of pigment formation. The error (mutation) may be in any or or more genes in the sequence, as well as also affected by other factors. Melanin in the human skin, hair and eyes can be classified into two groups: black to brown eumelanin (EM) and yellow to red pheomelanin (PM) Characterization of melanin in human iridal and choroidal melanocytes from eyes with various colored irides Kazumasa Wakamatsu 1 , Dan-Ning Hu 2 , Steven A. McCormick 2 , Shosuke Ito 1* 1 Department of Chemistry, Fujita Health University School of Health Sciences, Toyoake, Aichi, Japan 2 Tissue Culture Center, Departments of Pathology and Ophthalmology, The New York Eye and Ear Infirmary, New York Medical College, New York, NY, USA *Address correspondence to Shosuke Ito, e-mail: sito@fujita-hu.ac.jp Copyright 2007 The Authors, Journal Compilation 2007 Blackwell Munksgaard Type and quantity of melanin in growing uveal melanocytes from eyes with various colored irides In growing uveal melanocytes, the quantity of EM was correlated with iris color (Figure 2A). Uveal melanocytes from eyes with dark-colored irides (dark brown and brown irides) contained a significantly greater quantity of EM than that of cells from eyes with light-colored irides (blue, yellow-brown, green and hazel colored irides) (P less than 0.0001). A similar, but less pronounced difference was observed between dark brown and brown irides (P less than 0.05). The quantity of PM in uveal melanocytes from eyes with light-colored irides was slightly greater than that from dark-colored irides, although this was not statistically significant (Figure 2A). EM/PM ratio in uveal melanocytes was also related to iris color; the darker the iris color, the higher EM/PM ratio (Figure 2A). This indicates that darker melanocytes produce not only a higher quantity of melanin but also more eumelanic pigment than lighter melanocytes; melanocytes from dark brown irides contain 93% EM while those from blue irides contain only 44%. The total quantity of melanin (either EM + PM or TM) measured by HPLC or spectrophotometry, respectively, also correlated with iris color (Figure 2A). EM + PM and TM values in uveal melanocytes from eyes with dark-colored irides were greater than those from eyes with light-colored irides, and the difference was statistically significant (P less than 0.0001) (Figure 2A). Variance in iris color is related to the incidence of several important ocular diseases, including uveal melanoma and age-related macular degeneration. The purposes of this study were to determine the quantity and the types of melanin in cultured human uveal melanocytes in relation to the iris color. Sixty-one cell cultures of pure uveal melanocytes were isolated from donor eyes with various iris colors. The amount of eumelanin (EM) and pheomelanin (PM) of these cells was measured by chemical degradation and microanalytical high-performance liquid chromatography (HPLC) methods. The total amount of melanin was measured by both microanalytical methods and spectrophotometry. Total melanin content, measured by HPLC and spectrophotometry, correlated well with r = 0.872 (P less than 0.0001). The quantity and type of melanin in iridal and choroidal melanocytes showed no significant difference (P greater than 0.05). When cells became senescent, the levels of EM, PM and total melanin were significantly increased. In both growing and senescent melanocytes, the quantity and type of melanin were closely correlated to the iris color. In cells from eyes with dark-colored irides (dark brown and brown), the amount of EM, the ratio of EM/PM and total melanin were significantly greater than that from eyes with light-colored irides (hazel, green, yellow-brown and blue) (P less than 0.0001). The quantity of PM in uveal melanocytes from eyes with light-colored irides was slightly greater than that from dark-colored irides, although not statistically significant (P greater than 0.05). The present study shows that iris color is determined by both the quantity and the type of melanin in uveal melanocytes. These results suggest a possibility that uveal melanin in eyes with dark-colored irides is eumelanic at the surface and acts as an antioxidant while that in eyes with light-colored irides exposes pheomelanic core and behaves as a pro-oxidant. [/QB][/QUOTE]
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