• Question: Epigenetics is the study of the changes which can be made to DNA without changing the actual sequence of the DNA itself is this right?

    Asked by Ayse to Tristan, Sophie, Ravinder, Matt, Barbara on 7 Mar 2015.
    • Photo: Barbara Shih

      Barbara Shih answered on 7 Mar 2015:

      That’s correct. There are different epigenetic changes that can occur. One example (DNA methylation) would be chemical modifications that occur at DNA sequences at the beginning or near a gene. These modifications could make it easier or harder for the cell to’read’ the gene and thereby making more or less of the protein the gene codes for.

    • Photo: Sophie Robinson

      Sophie Robinson answered on 10 Mar 2015:

      This is very true. All our cells have exactly the same genes and DNA inside them, however a muscle cell and a white blood cell are very different. The reason they can be different and have the same DNA is because different genes are turned on and off in each of the cells by chemical modifications. This process is called epigenetics.

      When this process goes wrong it can have severe consequences. For instance a disease called FOP causes sufferers to be slowly imprisoned in their own skeletons. This happens when the gene for bone growth stays switched on in muscle cells when it would normally be turned off by epigenetic modifications. This results in patients’ muscle tissue slowly turning to bone. A very nasty disease indeed.

    • Photo: Matthew Moore

      Matthew Moore answered on 13 Mar 2015:

      Yes that’s true! Epigenetics can refer to chemical modifications to DNA bases such as the addition of a methyl group (methylation) which can affect how the genes are expressed.

      Additionally, DNA is wrapped around proteins called histones to make chromosomes. Chemical modification of the histone proteins can also impact on expression by making certain parts of the DNA available or not!

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