Melanin is the substance that gives skin, eyes and hair their colour. It is found in most living things. It makes squid ink and crow feathers black. Those without melanin are albinos.
Even white people have melanin in their skin – just less of it. Some whites have so little melanin you can clearly see blue veins through their skin. A low-level of melanin causes eyes to look grey, green, blue or even violet.
Melanin protects human skin from sun damage. It blocks the sun’s ultraviolet rays, preventing sunburn and skin cancer. Melanin also keeps the sun from breaking down vitamin B9, thereby preventing birth defects. Tanning is where the skin produces more melanin to protect itself.
Melanin comes in four main colours: black, brown, yellow and red. Think hair colours. When hair turns from black to grey to white it is losing its black melanin. The colours can be mixed in different amounts. The pink undertone of white skin comes from blood, not melanin. Dark skin, hair and eyes have more melanin than light ones.
Black skin goes back at least 1.2 million years. As early man lost his body hair, his skin turned brown to protect it from the African sun. This is genetically the same skin people still have in Africa, South Asia and Melanesia.
Light skin appeared in north Eurasia about 55,000 years ago. When people moved into Europe and East Asia their skin became lighter still but in genetically different ways. Europeans did not reach their present whiteness till about 6,000 to 12,000 years ago through a mutation to the SLC24A5 gene. That is when they started getting blue eyes too (from a separate mutation).
Black skin is overkill if you live more than 36 degrees from the equator: Europe, northern Asia, Canada, the American North, New Zealand, Tasmania, Argentina, Chile, etc. There the sun is so weak that black skin cannot produce enough vitamin D except in summer. Before the 1900s, back when diets were poor, that meant a greater chance of ricketts, which meant badly formed bones, which meant more women dying in childbirth. Light skin did not have this drawback.
Melanin Theory: Some say whites are cold-hearted, warlike, unspiritual and so on because they suffer from melanin deficiency. More melanin makes you more fully human. This is not supported by the science:
There is melanin in the brain. It even seems to affect how easily people get hooked on drugs and alcohol. But the amount of melanin in your skin does not necessarily match the amount in your brain.
On the other hand, darker skinned people are less likely to get Parkinson’s disease and, when they smoke, smoke more heavily. Melanin might affect those things.
Dr Frances Cress Welsing, a psychiatrist, says whites fear being wiped out genetically by those with more melanin. That is why they feel the need to control people of colour and keep them down.