• Question: why are humans different colors to each other and not all the same color

    Asked by anon-220639 on 12 Jun 2019.
    • Photo: Rachel Hardy

      Rachel Hardy answered on 12 Jun 2019:

      Great question 🙂 Our skin colour is controlled by a pigment called melanin. This is made by special cells in the skin known as melanocytes. Melanin is made in different forms, including eumelanin and pheomelanin. People with darker skin tend to produce more eumelanin, while people with paler skin tend to produce more pheomelanin. The amount of each melanin pigment that we have is determined by our genes – which are inherited from our parents. The melanocyte cells that make melanin also behave differently in different humans. Melanocytes in some people will produce a lot of melanin, which produces a darker skin tone (compared to lighter skinned people who have melanocytes that make less melanin). Some people also naturally possess fewer melanocytes than others, resulting in less melanin being produced (and lighter skin). When we are exposed to sunlight, the UV radiation causes melanocytes to release melanin. This causes our skin to darken, resulting in a sun tan.

    • Photo: Rebecca Moon

      Rebecca Moon answered on 12 Jun 2019:

      Skin pigmentation is determined by melanin within the skin which is produced by melanocytes. Higher levels of melanin protect against sun burn and UV radiation damage, but darker skin types are less capable of making vitamin D within the skin. Anthropologically there would have been advantages to the different level of skin pigmentation depending on geographical location (likely sun exposure) and if “survival of the fittest” Darwinian theory is applied, this would have resulted in different skin types predominating in different geographical areas.

    • Photo: Kaitlin Wade

      Kaitlin Wade answered on 13 Jun 2019:

      Rachel and Rebecca have answered this really well. All about melanin and where people live!

    • Photo: Matthew Bareford

      Matthew Bareford answered on 14 Jun 2019:

      This is because of a substance produced by the body called melanin. This is also found in hair and is the reason for the different colours people have here too.

      Melanin is produced in two different types, one is brown or black and the other red or yellow. this then get transported to the skin. It is the amount of each of these in that mixture that determines the colour of a persons skin.

      The melanin will act as a kind of shield for the cells in order to protect them from the suns harmful rays. This is why people in much sunnier and hot places tend to have darker skin colour

    • Photo: Nina Rzechorzek

      Nina Rzechorzek answered on 15 Jun 2019:

      The others have answered this really well, so just thought I’d add some interesting facts:

      The colours we see in feathers, fur and skin in non-human animals are also largely determined by melanocytes
      Furred animals such as mice lack epidermal melanocytes (except in non-hair-bearing sites such as the ear, nose and paws).
      Polar bears have hollow unpigmented fur to blend in with the environment but, unlike other furred animals, have a high density of epidermal melanocytes, which aid in heat retention and produce black skin most notable in non-furred areas!
      Melanocytes are also found in the choroid layer at the the back of the eye, in the iris, the leptomeninges (a thin covering of the brain) and the stria vascularis of the cochlea (the inner ear) – the absence of melanocytes in the stria vascularis is thought to lead to the degeneration of this structure and may explain pigment-associated deafness in certain dog breeds such as Dalmatians!
      The degree of melanin production is the most useful predictor of human skin cancer risk in the general population – but it is important to remember that ANYONE can get skin cancer

      Here is up-to-date info on melanoma (the deadliest form of skin cancer)
      https://www.cancerresearchuk.org/health-professional/cancer-statistics/statistics-by-cancer-type/melanoma-skin-cancer

    • Photo: Kate Timms

      Kate Timms answered on 17 Jun 2019:

      Our skin pigmentation (melanin) affects how well we can make vitamin D with the help of sunlight, the less melanin the better we can do it. But, melanin also protects us from solar radiation that causes skin cancer and ‘burns’. So its a bit of a trade off between the two depending on where in the world you’re from. Our skin colours change to help us reach a happy medium between the two!

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