urvival of some human groups, according to Steegman, 1967, and may have been one of several factors responsible for the evolution of white skin. Reports on Senegalese troops during World War I and Ethiopian troops during the Korean War showed higher rates of frostbite and frozen feet in the African soldiers than their European counterparts. The laboratory work of the researchers also suggested that black skin tissue was more prone to cold injury; however, white skin also exhibited some damage. It was discovered that these samples of black skin tissue were less vulnerable to cold damage than the lighter European tissue. Anthropologists believe that there are no substantial genetic differences between human populations, but biochemically, Caucasians have a higher concentration of enzyme inhibitors that suppress melanin production, according to Halprin & Ohkawara, 1966. Asians also have enzymes that inhibit melanin production, but significantly less than Caucasians. Therefore, there are genetic differences that have evolved to allow for the many colors expressed in human skin. Human skin is responsible for the synthesis of vitamin D. Ultraviolet radiation absorption by the skin converts 7-dehydrocholesterol (7-DHC) to vitamin D. Vitamin D is essential for normal growth and skeletal development. Vitamin D deficiency causes immobilization, pelvic deformities, tickets, and even death. The dark-skinned African migrants in Europe during the late Pleistocene, whom produce Vitamin D with the assistance of the sun received less UV light due to the cloudy, cold climate. Their protective clothing and shelters blocked sunlight from entering the skin, causing less vitamin D production. Due to the resulting vitamin D deficiency, extreme cases of bone deformalities may have ensued. These deformities significantly reduced reproductive efficiency, adding to natural selection. Pelvic deformities, as a result of rickets, may have reduced the life ...
