• Question: What is melanin?

    Asked by nilokoko to Sarah, Will on 22 Jun 2012. This question was also asked by ciaralydon.
    • Photo: Will Reynolds

      Will Reynolds answered on 22 Jun 2012:

      Hi nilokoko. Melanin is a brown pigment made from the amino acid tyrosine that is found is most living things. In humans melanin is produced by melanocytes in the skin to protect us from harmful UV radiation. When UV radiation hits our skin it damages our DNA which triggers the production of more melanin, which is what causes a suntan. Hope this helps!

    • Photo: Sarah Martin

      Sarah Martin answered on 22 Jun 2012:

      Hi nilokoko,

      It’s what makes our skin darker than pink and white, and out hair coloured, and eyes brown – at least in people with brown eyes.

      In the skin it’s in the top layer, here:

      and its chemical structure is here:

      The making of melanin is actually controlled by at least 5 different genes! Most differences between people with different colour of skin, hair an eyes is down to a single swap of one DNA molecule out of hundreds in one of these genes, which makes the melanocytes work differently.
      This was a really important swap in evolution, when humans first moved to Europe and would have struggled to get enough sun to make vitamin D had they kept their darker skin, which protects from sunlight.

      🙂 Sarah

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