Why do most human bodies tan when exposed to UV light? Explain the possible relationships between...

Why do most human bodies tan when exposed to UV light? Explain the possible relationships between ultraviolet light, vitamin D, folic acid and melanin production with regard to the evolution of various skin colors in human population

Expert Solution

Exposure to ultraviolet rays causes certain skin cells to produce the pigment melanin, which darkens through oxidation.

There is the general trend of populations becoming lighter as one moves away from the tropics. The close relationship between vitamin D and UVR forms the basis of the “vitamin D–folate hypothesis”, The hypothesis proposes that skin pigmentation has evolved as a balancing mechanism, maintaining levels of these vitamins. Folate may have a role in melanogenesis by regulating the production and stabilisation of tetrahydrobiopterin. Tetrahydrobiopterin is a required cofactor for tyrosine hydroxylase, which converts tyrosine into dopa in the production of melanin pigments. It could be suggested that folate and melanin compounds are synergistic; melanin, on the one hand, protects folate from UVR-related degradation, which in turn supports the influence of folate in melanogenesis.

gladiator answered 2 years ago

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