Why does tanning ability differ substantially between individuals with similar epidermal melanin content but varied genetic ancestry?

💡 Explanation

Individuals may have similar melanin content, but variations in the melanocortin 1 receptor (MC1R) signaling pathway affect the efficiency of melanogenesis in response to UV exposure; therefore, tanning ability varies, rather than being solely dependent on baseline melanin levels, because MC1R controls melanin type and quantity.

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