Biology of Skin Color Assignment

Techniques to track the relative origin location of all people can be used to determine the relatedness between you and other people in your family. Unique genetic marks allows for easy understanding of where populations came from. Archeological evidence and DNA evidence from people all around the world supports human migration out of Africa. You can see this in the image below.

Human Migration out of Africa

You may already know there is a correlation between UV and skin color. After reviewing the Human Migration out of Africa and Figure 1 and 2. It poses the question, “Why aren’t we all black?” Since humans migrated out of Africa, why did people lose pigment after they migrated to certain areas? Why does indeginious skin color mimic UV exposure throughout the earth? There have been several explanations for decades that do not hold up, such as, lighter skinned people may have an advantage where it snows. Natural Selection says that the fittest organisms in their environment will survive at least long enough to reproduce.

We now know that melanin is the protein that gives skin color and, more importantly, protects the nucleus (the thing that holds DNA) from UV radiation from the sun. Without any melanin the sun may feel like your mortal enemy. Too much UV from the sun and no melanin to protect your nucleus can, and will, eventually cause skin cancer. You may already know that we need sunlight to help make vitamin D. This vitamin allows bones to develop and maintain properly. The more melanin you have, the more sun you need to make vitamin D because melanin acts as a sun blocker.  Inversely, too much unprotected sun exposure can reduce levels of folic acid during pregnancy. low level of the vitamin folic acid yields a high risk of miscarriage. No wonder all prenatal vitamins include folic acid and vitamin D.

“Melanin” is the collective term for a family of pigment molecules found in most organisms, from bacteria to
humans, suggesting that melanin has a long evolutionary history and a broad range of important functions.
In humans, melanin pigments are found mainly in human skin, hair, and eyes, and they include reddish-yellow
pheomelanin and brown and black eumelanins. In human skin, melanin pigments are synthesized in organelles called melanosomes that are found in specialized cells called melanocytes in the skin epidermis. Once the melanosomes are filled with a genetically determined amount and type of melanin, they migrate to other skin cells called keratinocytes.