Human skin color: Origin, variation and significance

The document discussed the evolution and significance of human skin color, emphasizing the role of melanin in protecting against solar radiation. Melanin is produced by melanocytes and transferred to keratinocytes, with skin and hair color determined by the quantity and quality of melanosomes. Eumelanin (black-brown) is found in all pigmented sites, while pheomelanin (yellow-red) is specific to hair follicles. Albinism results from defects in melanin synthesis. Human skin pigmentation follows a general mammalian pattern, with ethnic variations likely influenced by three to six gene pairs. The document also noted that while melanin has functions beyond photoprotection, many proposed adaptive functions are speculative.