Human skin color within a "fair/medium/olive" context. Oculocutaneous albinism (OCA) is a lack of pigment in the eyes, skin and sometimes hair that occurs in a very small fraction of the population. The four known types of "OCA" are caused by mutations in the "TYR", "OCA2", "TYRP1", and "SLC45A2" genes. In hominids, the parts of the body not covered with hair, like the face and the back of the hands, start out pale in infants and turn darker as the skin is exposed to more sun. All human babies are born pale, regardless of what their adult color will be. In humans, melanin
Biological pigment with a simple protein (glycoprotein). The second type, Type B, has carotenoids which are associated with a lipo protein and is usually less stable. While Type A is commonly found in the surface (shells and skins) of marine invertebrates, Type B is usually in eggs, ovaries, and blood. The colors and characteristic absorption of these carotenoprotein complexes are based upon the chemical binding of the chromogen and the protein subunits. For example, the blue carotenoprotein, linckiacyanin has about 100-200 carotenoid molecules per every complex. In addition, the functions of these pigment-protein complexes also change their chemical structure as well. Carotenoproteins