Question: Can you explain the role played by these on and off switches in epigenetics?

Asked by monkeyboy to Kate on 11 Mar 2013.

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  1. Photo: Kate SkulteKate Skulte
    answered on 11 Mar 2013:

    Hi Monkeyboy, thanks for your question!

    The ON and OFF switches in our DNA are tell our genes when they are needed. A lot of our genes are not active until an ON switch gives them the green light.

    These switches are a type of epigenetic control. Epigentics refers to all the chemical modifications and changes to our DNA, which do not change the sequence. This includes when chemical groups attach themseleves to DNA, when proteins compact or unwind DNA, and when other proteins bend and loop DNA into different 3D shapes.

    Whether DNA is compact or unwound is really important for how these switches work. When DNA is unwound, the ON switch can access the gene to turn it on. When DNA is compact the gene will be buried in a mix of DNA and protein and not accessible to the ON switch.

    Most of the switches are not next to the gene they activate so they also need the help of proteins that bend DNA to move them to their target. This can get really complicated because some switches control more than one gene.

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