More on the origin of skin colors for consideration

EXTRACT FROM: A fish of a different color

February 2006

"But how did different ethnic groups wind up with these different versions of the pigmentation gene? Research suggests that more than 100,000 years ago, the earliest humans lived in Africa and carried the "G" allele, which causes lots of melanin to be present in skin cells and hence, dark skin. Melanin absorbs UV rays from the sun and controls the amount of UV radiation that penetrates our skin. Our bodies need some UV radiation (to build the essential vitamin, vitamin D) but not too much (because UV radiation can damage the skin and destroy another essential vitamin, folate). In the sun-drenched environs of Africa, dark skin was advantageous, preventing UV rays from doing too much damage, while allowing in enough UV to synthesize vitamin D. In that environment, individuals born with a mutant version of the gene associated with less melanin and lighter skin would probably have had poor health and low reproductive success.

Many biologists hypothesize that between 55,000 and 85,000 years ago, humans began to migrate out of Africa. Some of them wound up living in the colder, darker climes of Europe. There, too much UV radiation was not a problem, but too little UV to synthesize vitamin D probably was. At some point either before or after the migration out of Africa, a mutation occurred in one of the ancestors of modern Europeans. This mutation was tiny, changing just a single base, but it caused much less melanin to be present in the skin of those who carried the mutation. This was the "A" allele. Among the new Europeans, this allele likely had an advantage over the "G" allele. Individuals carrying the "A" allele had less melanin, which allowed more UV light to penetrate their skin, which could have allowed them to synthesize vitamin D better than those carrying only the "G" allele. These "A"-carrying individuals had increased reproductive success in their sun-poor environment, and via natural selection, the "A" allele spread throughout the European population. Meanwhile, among Africans, the "G" allele continued to be advantageous and to maintain its majority there.

Full Article ...
http://evolution.berkeley.edu/evolibrary/news/060201_zebrafish

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P.S: Actually, Dr. Frances Cress Welsing's 'The Isis Papers' is a worthwhile book to read. I read it many years ago. You will rarely find Black activists dissing Dr. Frances Cress Welsing outright, not that they all totally agree with her theories, but because she is respected for trying to provide answers in areas of concern to Africans. Her passion is in the right place and I do recommend her book. Dr. Welsing also mentions Neely Fuller's 'The United Independent System Code Concept' in her book.

-Ayinde