What causes the variation in skin coloration in individuals with darker skin?

The variation in skin coloration observed in individuals with darker skin is primarily due to higher concentrations of melanin. Melanin is the pigment responsible for skin, hair, and eye color and is produced by specialized cells known as melanocytes. In darker-skinned individuals, these melanocytes produce more melanin, which provides not only coloration but also offers some protection against the damaging effects of ultraviolet (UV) radiation from the sun. This increased melanin concentration results in a darker skin tone, which can help mitigate the risk of UV-related skin damage.

Other factors, such as thicker epidermis or increased blood flow, may influence the overall appearance of the skin but do not directly account for the primary reason behind variations in skin color, which is the amount and type of melanin present. Likewise, lower keratin production relates more to skin texture and barrier function rather than pigmentation itself. Thus, the higher concentrations of melanin are the key factor driving the differences in skin coloration among individuals.