What differentiates skin colour

Question: What differentiates skin colour
- Keywords:
  colour,
  skin
Asked by King.Bach to Claire, Franco, Koi, Linda, Mark on 14 Jun 2016.
- Franco Falcone answered on 14 Jun 2016:
  
  @KingBach
  
  very good question. As you are exposed to hard UV radiation, which damages DNA and can cause cancer, your skin protects itself by creating a pigment called melanin, which absorbs the UV-B radiation and neutralises its effects. The more melanin you have, the darker your skin
  
  There is a problem however. You do need to have some UV on your skin to make Vitamin D. If you are living in tropical countries, you still get enough sun for Vitamin D synthesis even if your skin is dark. If however you live in Northern countries such as Northern Europe, then if you have dark skin you don’t get enough sun and you are more likely to become Vitamin -D deficient in the long term. Of course you can take dietary supplements so that’s not a real problem.
  
  This is why when the ancestors who settled Europe and Asia, and later the Americas, left East Africa 100.000 years ago or so, progressively lost some of their skin pigmentation, as a compromise between skin protection and the ability to produce Vitamin D in the skin
- Linda Anagu answered on 14 Jun 2016:
  
  @King.Bach, a skin pigment called melanin differentiates skin colour. The more melanin you have the darker you would be. Africans have darker skin and thus more melanin and this helps protect their skin from UV rays because they are constantly exposed to so much UV rays from the sun. however, this also means that they make less vitamin D than a lighter skin colour individual, like a Briton. With the spare sunshine in this country, the lighter skinned person will be able to get enough vitamin D than a darker individual.
  
  Note of warning: if you are lighter skin, put on a sunscreen on a sunny day as prolonged exposure to damaging UV rays can lead to skin cancer
- Claire Bourke answered on 14 Jun 2016:
  
  Great answers from Linda and Franco there.
  
  My genetic background is from Northern Europe so I have low melanin pigments in my skin and need to protect myself from too much sun. Melanin is produced as granules by specialised cells called melanocytes and, on skin like mine, you can see patches of darker skin called ‘freckles’ when exposed to the sun, which are caused by overproduction of melanin by nearby melanocytes in response to the sun’s UV radiation.
- Arporn Wangwiwatsin answered on 14 Jun 2016:
  
  Hi King.Bach,
  I agree with the answers well covered by Franco, Linda, and Claire already. Nice one!
  This is one of examples for how living things change and adapt with the environment they are in… in a long term, over many generations, evolution come in to play and the colour of skin became embedded within our genome which tell cells on skin how much melanin to produce and that gives us the baseline of the skin colour. Whereas in a much shorter terms we can “adapt” to change in environment, like staying in strong sunlight for long and get tan.
  
  And interestingly, melanin is not only responsible for different skin colour but it also responsible for eye colours and hair colours too!
- Mark Booth answered on 16 Jun 2016:
  
  Hi King.Bach
  
  There is a population genetics answer to this question that draws on Claire’s and Franco’s answers. The origins of homo sapiens and the mass migration of people from central-eastern Africa has been demonstrated through analysis of genetic diversity data. There may have been a selection pressure on travellers that favoured those with mutations in the genes that produce melanin as Franco indicates. But diet is also important and there may have been a number of evolutionary tradeoffs at work due to the different diets that would have been consumed by travellers compared to those who stayed in Africa.

Question: What differentiates skin colour

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