B IOLOGY O F S KIN C OLOR (Sub-Saharan African, Indian, Southern European, and Northern European)

There are no people who actually have true black, white, red, or yellow skin. These are commonly used color terms that do not reflect biological reality.

S KIN COLOR AND RACE There are NO reliable genetic markers for race. (ie. There is no gene for race) The concept of race is questionable! The “false” concept of race can be traced to the history of European colonization- people really like to categorize. As a species, all humans originated in Africa.

The brown color we all share is melanin produced my the melanocytes at the lowest level of the epidermis. Protection for UV light. The skin uses UV light to synthesize vitamin D, BUT approximately an hour a week is all that is needed. ALSO, and important to human evolution, UV breaks down folic acid (Vitamin B) in the body. A lack of folic acid can lead to birth defects & deformed sperm

G EOGRAPHY Near the equator the amount of sunlight is much more than what is needed to synthesize vit D. Too much exposure increases the risk of birth defects (lack of folic acid), defective sperm & skin cancer. Thus, an increase in melanin (which absorbs UV and protects the folic acid & DNA) was selected for since humans with more melanin more likely to survive.

E VOLUTION OF S KIN C OLOR Evolution of humans near the equator in Africa benifited from an increase in the production of melanin. As people migrated, particularly far north of the equator (less intensity and length of light) the need for UV (vitamin D) outweighed the protection from destruction of folic acid & UV (birth defects & cancer).

(Data for native populations collected by R. Biasutti prior to 1940.)

Very little of the skin is actually involved in skin- color difference. Everyone has melanin. The ONLY difference is the amount of melanin.