Answer to Question #7898 in Other Biology for jack
how natural hair pigments influence the colour selection
Hair color is determined by the content of the two pigments - eumelanin and pheomelanin. The last has a reddish tone. If the organism synthesizes a large amount of melanin, reddish hues of pheomelanin are almost invisible, and obtains the dark hair. In a case of a pheomelanin presence on a weak melanin background, the hair, by contrast, takes on a reddish tone. Otherwise, the small melanin amount without pheomelanin will result in a light gray and light ash color of the hair.