Skin color

The color of skin which is complexly determined.

Skin color depends on many factors including reddening caused by inflammation, the hemoglobin level in the blood, and the darkening caused by increased deposition of the pigment melanin.

Melanin itself is a polymer that comes in two types -- a red-yellow form known as pheomelanin and a black-brown form known as eumelanin.

The genetics of skin color are similarly complex.

Skin color is clearly polygenic, determined by a number of genes.

These genes include TYR (tyrosinase), MATP (membrane-associated transport protein) and P (the pink-eyed dilution protein).

There may be 20 or so other genes that affect skin color.