• Question: How comes our nails and hair are made out of the same keratin?

    Asked by to Rebecca, Ditte, Dave, Ben on 20 Jun 2014. This question was also asked by .
    • Photo: Rebecca Gladstone

      Rebecca Gladstone answered on 20 Jun 2014:

      Keratin is a tough protein that is organised into long strands. You are right it is present in our hair and nails, did you know that it is also part of our skin? Hair, skin and nails have something in common, they are there to protect us from getting damaged and hurting ourselves. To do this they need to be strong and use keratin to help them. The strands can be arranged in different ways, like bundled together and coiled up giving them different strength for different purposes. The amount of keratin protein used in skin cells, in hair and nails also differs so they end up looking different too.

    • Photo: Ben White

      Ben White answered on 22 Jun 2014:

      There are primarily two types of keratin:
      α-keratins are found in hair, nails, horns and hooves.
      β-keratins are mostly found in reptiles, in their hard scales and claw.
      It is the way in which the bonds interact with each other in the structure of these keratins, and how the molecules are layered upon each other, that affect the shape and toughness of the keratin; as Rebecca said below.

    • Photo: Ditte Hedegaard

      Ditte Hedegaard answered on 24 Jun 2014:

      Hi 11zmahmood

      It is weird to think that our hair and nails consists on the same keratin when they are so different, but when you think about it from an evolutionary point it kind of make sense. Our gene material is very compact and there is no reason to have 2 genes for keratin, one for hair and one for nails, when they basically have the same function (e.g. a hard material which can protect us from damage and heat and help us keep our skin clean by scratching, just like Rebecca says). Primitive organisms like bacteria has the ability to get rid of one gene if they have two of the same gene. This means that they do not have to keep both of them active and can therefore save. Perhaps humans ancestors did the same millions of years ago for the keratine genes and that is why we have the same keratin in nails and hair.

      This is only speculations, we would have to look at genes in our closest living relatives, the chimpanzee and other animals, to find out if we have always had one type of keratin or if our ancestors use to have two.

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