Melanocyte

Melanocytes are cells located in the bottom layer of the skin's epidermis. They produce menalin, a pigment in the skin, eyes, and hair. In Caucasion people, these are triggered by ultraviolet rays, thus they have to be in the sunlight to tan. In other people, these are constantly producing menalin. Melanocytes range between 1,000 to 2,000 per square millimeter of skin. The difference between fair people and dark people is not the amount of melanocytes, but how active the menalocytes are.

Albinos are lacking an enzyme, tyrosinase, which is required for melanocytes to produce melanin.