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How did melanin help protect people living in areas with strong sunlight?

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Overhead view of a diverse group of people standing in a circle, holding each other's hands in a gesture of unity and teamwork. — Race Skin color is one of the variables that has been used to classify people into different racial categories.

Melanin serves as a vital protective mechanism for human populations living in regions with intense sunlight. Produced by specialized cells called melanocytes, this pigment acts as a natural shield against the harmful effects of ultraviolet radiation.12

When melanin is transferred to neighboring epidermal cells, the granules often position themselves above the cell nucleus, forming a protective shroud that helps prevent damage to cellular structures. By absorbing and scattering ultraviolet rays, melanin provides essential protection against sunburn and skin cancers, which are significant risks in areas where sunlight is strongest.132

While this pigmentation is highly adaptive in tropical environments, it represents a balance in human evolution. Because sunlight is also required for the body to synthesize vitamin D, natural selection favored different levels of melanin depending on the latitude; populations in northern climates with limited sunlight evolved lower levels of melanin to ensure sufficient vitamin D production, whereas those in high-sunlight regions retained higher levels to protect against radiation damage.32