Black hair


Black hair is the darkest and most common of all human hair colors globally, due to larger populations with this dominant trait. It is a dominant genetic trait, and it is found in people of all backgrounds and ethnicities. It has large amounts of eumelanin and is less dense than other hair colors. In English, various types of black hair are sometimes described as soft-black, raven black, or jet-black. The range of skin colors associated with black hair is vast, ranging from the palest of light skin tones to dark skin. Black-haired humans can have dark or light eyes.

Distribution

Though this characteristic can also be seen in people of the United Kingdom and Northwestern Europe, it is less common. People of Celtic heritage in Ireland with such traits are sometimes known as the "Black Irish".
Hair is naturally reflective, so black hair is not completely dark in bright light. However, the darkest shade will not have a warm, neutral tone but a sheen which can seem almost blue, like the iridescence of a raven's wing; hence, sometimes referred to as raven-black.

Genetics

Black-haired people of Amerindian, East Asian, or Southeast Asian ancestry have thicker and straighter hair due to the Derived EDAR gene allele that is linked to thicker and straighter hair and shovel-shaped incisors. The derived EDAR gene arose approximately 30,000 years ago in China. One study shows that Paleo-Indians had both variants of the EDAR gene, the derived G-allele and the ancestral A-allele. When they tested ancient DNA remains found in the Americas of the individuals named USR1, Anzick-1 and Laranjal-6700 the results showed that they carried the ancestral A-allele.
11,000-year-old remains of Cuncaicha and Lauricocha individuals from South America share alleles at the highest rate with present-day Amerindians, indicating that the derived G-allele increased in frequency in parallel with the ancestral A-allele.

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