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There is evidence that as many as 16 different genes could be responsible for eye color in humans; however, the main two genes associated with eye color variation are OCA2 and HERC2, and both are localized in chromosome 15. [10] The gene OCA2 (OMIM: 203200), when in a variant form, causes the pink eye color and hypopigmentation common in human ...
Researchers studying the opsin genes responsible for color-vision pigments have long known that four photopigment opsins exist in birds, reptiles and teleost fish. [3] This indicates that the common ancestor of amphibians and amniotes (≈350 million years ago) had tetrachromatic vision — the ability to see four dimensions of color.
Color vision deficiencies can be classified as inherited or acquired. Inherited: inherited or congenital/genetic color vision deficiencies are most commonly caused by mutations of the genes encoding opsin proteins. However, several other genes can also lead to less common and/or more severe forms of color blindness.
Color vision is categorized foremost according to the dimensionality of the color gamut, which is defined by the number of primaries required to represent the color vision. This is generally equal to the number of photopsins expressed: a correlation that holds for vertebrates but not invertebrates .
Illustration of the distribution of cone cells in the fovea of an individual with normal color vision (left), and a color blind (protanopic) retina. Note that the center of the fovea holds very few blue-sensitive cones. Distribution of rods and cones along a line passing through the fovea and the blind spot of a human eye [11]
And of course, the genes we inherit from our parents play a significant role in determining our eye color. There are two main types of melanin that contribute to eye color: eumelanin and pheomelanin.
Gene therapy is a general treatment for genetic disorders; it uses viral vectors to carry typical genes into cells (e.g. cone cells) that are not able to express functional genes (e.g. photopsins). It may be possible to restore color vision by adding missing opsin genes – or a functional copy of the entire gene complex – into
The reason boils down to genes. A senior lecturer in biomolecular sciences at Liverpool John Moores University said, "What we know now is that eye color is based on 12 to 13 individual variations ...