Eye color

Eye color or eye colour is a polygenic phenotypic character determined by two distinct factors: the pigmentation of the eye's iris and the frequency-dependence of the scattering of light by the turbid medium in the stroma of the iris.

In humans, the pigmentation of the iris varies from light brown to black, depending on the concentration of melanin in the iris pigment epithelium (located on the back of the iris), the melanin content within the iris stroma (located at the front of the iris), and the cellular density of the stroma. The appearance of blue and green, as well as hazel eyes, results from the Tyndall scattering of light in the stroma, a phenomenon similar to that which accounts for the blueness of the sky called Rayleigh scattering. Neither blue nor green pigments are ever present in the human iris or ocular fluid. Eye color is thus an instance of structural color and varies depending on the lighting conditions, especially for lighter-colored eyes.

The brightly colored eyes of many bird species result from the presence of other pigments, such as pteridines, purines, and carotenoids. Humans and other animals have many phenotypic variations in eye color. The genetics of eye color are complicated, and color is determined by multiple genes. So far, as many as 15 genes have been associated with eye color inheritance. Some of the eye-color genes include OCA2 and HERC2. The earlier belief that blue eye color is a simple recessive trait has been shown to be incorrect. The genetics of eye color are so complex that almost any parent-child combination of eye colors can occur. However, OCA2 gene polymorphism, close to proximal 5′ regulatory region, explains most human eye-color variation.

Blue eyes (disambiguation)

Blue eyes is a common eye color.

It may also refer to:

Places

Music

Film

Other uses

Blue Eyes (film)

Blue Eyes (Portuguese: Olhos Azuis) is a 2009 Brazilian drama film directed by José Joffily.

Plot

Not satisfied with the retirement and on his last day at the job, a U.S. immigration officer holds arbitrarily Latin passengers inside a room of a New York airport. There he conducts interrogations that takes a surprising and tragic course.

Cast

References

External links