Eli5: What’s the biological reason behind humans having eyes(irises) of different color?

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I know that eye color is directly related to the amount of melanin present in the front layers of the iris. But what’s the biological need behind different color?

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Anonymous 0 Comments

There probably isn’t a reason for it. Mutations don’t have to have any advantage in order to become part of our genetic makeup, as long as they don’t have any great disadvantage. Tens of thousands of years ago, someone was probably just born with different colored eyes, and it didn’t make him less likely to survive and pass on those genes, so it became part of the normal range of human eye colors.

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