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The total number of genes that contribute to eye color is unknown, but there are a few likely candidates. A study in Rotterdam (2009) found that it was possible to predict eye color with more than 90% accuracy for brown and blue using just six SNPs. [16] [17] In humans, eye color is a highly sexually dimorphic trait. [18]
Alternatively, it has been suggested that gray and blue eyes might differ in the concentration of melanin at the front of the stroma. [60] Gray eyes can also be found among the Algerian Shawia people [61] of the Aurès Mountains in Northwest Africa, in the Middle East/West Asia, Central Asia, and South Asia. Under magnification, gray eyes ...
The human eye's red-to-green and blue-to-yellow values of each one-wavelength visible color [citation needed] Human color sensation is defined by the sensitivity curves (shown here normalized) of the three kinds of cone cells: respectively the short-, medium- and long-wavelength types.
Human eye pigmentation in Europe Among human phenotypes, blue-green-gray eyes are a relatively rare [citation needed] eye color and the exact color is often perceived to vary according to its surroundings. The iris is usually strongly pigmented, with the color typically ranging between brown, hazel, green, gray, and blue.
Heterochromia is a variation in coloration most often used to describe color differences of the iris, but can also be applied to color variation of hair [1] or skin. Heterochromia is determined by the production, delivery, and concentration of melanin (a pigment). It may be inherited, or caused by genetic mosaicism, chimerism, disease, or ...
The human eye, showing the iris and pupil. In 1802, philosopher William Paley called it a miracle of "design."In 1859, Charles Darwin himself wrote in his Origin of Species, that the evolution of the eye by natural selection seemed at first glance "absurd in the highest possible degree". [3]
Monochromacy (from Greek mono, meaning "one" and chromo, meaning "color") is the ability of organisms to perceive only light intensity without respect to spectral composition. Organisms with monochromacy lack color vision and can only see in shades of grey ranging from black to white. Organisms with monochromacy are called monochromats.
Categorization of racial groups by reference to skin color is common in classical antiquity. [7] For example, it is found in e.g. Physiognomica, a Greek treatise dated to c. 300 BC. The transmission of the "color terminology" for race from antiquity to early anthropology in 17th century Europe took place via rabbinical literature.