Red hair is the rarest natural hair color in humans. The pale skin associated with red hair may have been advantageous in far-northern climates where sunlight is scarce
The pigment pheomelanin gives red hair its distinctive color. Red hair has far more of the pigment pheomelanin than it has of the dark pigment eumelanin.
The genetics of red hair, discovered in 1997, appear to be associated with the melanocortin-1 receptor (MC1R), which is found on chromosome 16. Red hair is associated with fair skin color because of low concentrations of eumelanin throughout the body of those with red hair.