#Blonde hair colors full#

Piebaldism is a rare autosomal dominant disorder of melanocyte development, which may cause a congenital white forelock. At some point in the human life cycle, cells that are located in the base of the hair's follicles slow, and eventually stop producing pigment. In some cases, gray hair may be caused by thyroid deficiencies, Waardenburg syndrome or a vitamin B 12 deficiency. Gray hair color typically occurs naturally as people age (see aging or achromotrichia below). The clear hairs appear as gray or white because of the way light is reflected from the hairs.

Gray or white hair is not caused by a true gray or white pigment, but is due to a lack of pigmentation and melanin. White hair is commonly seen in elderly people The scale uses the following designations: A (very light blond), B to E (light blond), F to L ( blond), M to O (dark blond), P to T ( light brown to brown), U to Y (dark brown to black) and Roman numerals I to IV ( red) and V to VI (red blond). The Fischer–Saller scale, named after Eugen Fischer and Karl Saller, is used in physical anthropology and medicine to determine the shades of hair color. Natural hair color can be black, brown, red, blond, or white. Blond hair results from small amounts of brown eumelanin with no black eumelanin. If there is no black eumelanin, the result is strawberry blond. Pheomelanin is generally found in elevated concentrations in blond and red hair, representing about one-third of total melanin content. Over 95% of melanin content in black and brown hair is eumelanin. All human hair has some amount of both pigments.

Eumelanin, which has two subtypes of black or brown, determines the darkness of the hair color more black eumelanin leads to blacker hair, and more brown eumelanin to browner hair. UV radiation most commonly comes from the sun, and thus populations from places closer to the equator tend to have darker hair, because eumelanin is generally more photoprotective than pheomelanin. Ultraviolet radiation (UV radiation) triggers greater synthesis of several compounds, including pro-opiomelanocortin (POMC), α-MSH, and ACTH, the result being increased eumelanin production. In addition, other genetic and environmental factors can affect hair color in humans for instance, mutations in the melanocortin 1 receptor (MC1R) gene can lead to red or auburn hair, and exposure to ultraviolet radiation can damage hair and alter its pigmentation. ĭifferent hair color phenotypes arise primarily as a result of varying ratios of these two pigments in the human population, although Europeans show the greatest range in pigmentation overall. Inside the melanocytes, tyrosine is converted into L-DOPA and then L-dopaquinone, which in turn is formed into pheomelanin or eumelanin.

Two types of pigment give hair its color, black-brown eumelanin and reddish-brown/reddish-yellow pheomelanin, synthesized by melanocytes. identified 13 DNA variations across 11 different genes that could be used to predict hair color. Regulatory DNA is believed to be closely involved in pigmentation in humans in general, and a 2011 study by Branicki et al.

#Blonde hair colors full#

The full genetic basis of hair color is complex and not fully understood. See also: Human genetic variation and Race and genetics