Why Do People Have Different Colored Hair?

People with black hair have a concentration of black eumelanins in their hair. Black is the most common hair color, occurring in people from all backgrounds, because black hair is a dominant genetic trait. Black hair is the dominant hair color in Sub-Saharan Africa, among the native peoples of the Americas, Southern Europeans, North Africans, West Asians, and in the British Isles and parts of Central Europe. Scientists believe that black is the original hair color of the Homo sapiens species.

Brown hair is the second most common hair color, containing both eumelanins and pheomelanins, with greater concentrations of the brown eumelanins. It is the second most common hair color among humans, common in people from Central and Southern Europe, North Africa and Western Asia.

Blonde hair contains low levels of eumelanin pigment and originates in northern Europe, where the largest concentrations of blonde-haired people exist. The countries where the trait is most common are Estonia, Poland, the Netherlands, Latvia, Lithuania, Russia, Belarus, Sweden, Finland and Norway. A third of the Pashtun and Nuristani people of Afghanistan have blonde hair. Based on genetic tests, some scientists believe blonde hair appeared in human populations around 11,000 years ago.

Red hair contains high levels of pheomelanin and low levels of eumelanin. Red hair is the rarest of the hair colors, occurring in only 1 to 2 percent of the entire human population. Red hair is a characteristic of having two copies of recessive genes in chromosome 16. Geographically, red hair is associated with Ireland, Scotland, England and Wales, with the highest concentration, 13 percent, in Scotland. Red hair is also found throughout Europe. Red hair sometimes crops up among Ashkenazi Jews and residents of Morocco, with small populations in Iran and Argentina.

White or gray hair is a trait related to both aging and genetic diseases. As we age, the pheomelanins and eumelanins which give our hair its color are no longer produced by the root of the hair follicle. By the age of 40, most people begin to turn gray. The process is controlled by the genetic makeup of each person. Diseases can cause graying or whitening of the hair. Premature graying can occur in people who have Werner syndrome or pernicious anemia, or who smoke tobacco. Albinism, characterized by very little pigment in the hair, eyes and skin, causes white or pale blonde hair.