Question

Darker skin is more prevalent in high-UV areas. Dr. Jablonski proposed a hypothesis to explain the selective pressure for darker skin in these environments. On what evidence did she base this hypothesis?

Answer 1

In environments with a high level of UV radiation darker skin protects against the harmful effects of UV radiation. According to the evidence, melanin is found in the upper layer of the skin human and absorbs UV radiation, which protects cells against the harmful effects of UV light. The genetic determine the type of melanin and the amount of melanin present in the cells of an individual. Ultraviolet radiation causes damages DNA and disrupts normal chemical reactions in cells. These processes are greatly mitigated by eumelanin that is abundant in dark skin. This condition also gives protection of folate metabolism against deficiencies caused by strong UV radiation, there is evidence from epidemiological studies that indicates an association between dark pigmentation and a lower rate of neural tube defects due to lower decomposition rates folate.