Red hair is caused by a genetic mutation in the melanocortin 1 receptor (MC1R) gene, which is located on chromosome 16. This gene plays a crucial role in determining hair color by controlling the production of melanin pigments.
When someone inherits specific variants in the MC1R gene, it leads to a decrease in the production of eumelanin, the pigment responsible for dark hair colors, and an increase in pheomelanin, the pigment that gives hair its reddish hue.
Essentially, redheads have a higher concentration of pheomelanin than eumelanin, which gives their hair its distinctive color. This genetic trait is also linked to other characteristics like fair skin and freckles, as the MC1R gene also influences skin pigmentation.
The origin of red hair can be traced back to Central Asia, where the MC1R mutation is believed to have first occurred. It has since spread to other regions, particularly in Europe and North America.
