What is Freckle?
[[Image:freckled.jpg|thumbnail|right|230px|Extremely freckled girls. Freckles cover the face, chest and shoulders]] '''Freckles''' are clusters of concentrated [[melanin]] that are most often visible with a fair [[skin]] complexion. Freckles are predominantly found on the face, although they may appear on any skin exposed to the sun, such as the lips, neck, arms, neck, shoulders, back and chest. They are an [[heredity|inherited]] trait, caused by variation in the MC1R [[gene]] that is involved in the determination of red [[hair]], fair skin, and freckles.<ref>OMIM (Online Mendelian Inheritance in Man) [http://omim.org/entry/266300]</ref> Freckle formation is triggered through exposure to sunlight. Two types of melanin, the red pheomelanin and the black eumelanin, are present in human skin. Eumelanin protects against sunlight. People with red hair have mostly pheomelanin in their hair and skin and/or a reduced ability to produce eumelanin. This may explain why they fail to tan and are at risk from the [[ultraviolet radiation]] in sunlight.<ref> Valverde P. ''et al.'' 1995. Variants of the melanocyte-stimulating hormone receptor gene are associated with red hair and fair skin in humans. ''Nature Genet''. '''11''': 328-330</ref> About 1.5 billion people in the world have freckles. About 75 per cent of Filipino people have freckles. == References == {{Reflist}} [[Category:Human body features]] {{science-stub}}