• Question: How does DNA become altered in the body?

    Asked by anon-254365 to Florence on 14 May 2020.
    • Photo: Florence Lichou

      Florence Lichou answered on 14 May 2020: last edited 19 May 2020 12:07 pm

      Hi Emily! This is very interesting. First, you need to know that cells in your body aren’t fixed. They can grow, die but also divide do give rise to two new cells. When they divide they make a copy of their DNA so that the two “daughter” cells have the same DNA as the “mother” cells. This process happens very often in the body, notably in the gut, where cells have to regenerate a lot. In each cell, DNA is composed of a list of 6 billions “letters” (nucleotides, named A,T,G and C). Copying them is not an easy process and cells make some mistakes (add a T instead of A, forget a letter…). Hopefully, there is a very efficient repair mechanism that recognise the mistake and correct them. Unfortunately, sometimes (<1/1000) it doesn't succeed and the error remains. It is often not a problem as most regions of the DNA are not essential. But sometimes it affects an important part of the DNA and it can cause diseases such as cancer. Other elements can alter the DNA (even when the cells are not dividing) such as the environment: UV light, smoking….

Comments

  • Photo: Alena

    Alena commented on :

    Many things aggress our bodies all the time, the environment is full of ‘insults’ as we sometimes call them and many of them can induce changes in the DNA of our cells. The most common one is UV light from the sun, this is why we are constantly reminded to put cream on. What happens is that the UV light penetrates our skin cells all the way to the nucleus where the DNA is and because is it so high energy, it can cause the double stran to break. Our cells are very good at repairing themselves and usually the DNA integrity is restored, but constant exposure to the UV can end up causing too much damage that overwhelms the cell’s repair machinery which can either fail or make mistakes. This can result in changes in the DNA. There are many other factors that can change or mutate our DNA, one classic example is tobacco.