What is junk DNA?

Only around 5% of your DNA is thought of as coding DNA, or DNA with a function, so what is the rest of it for and is it really 'junk'?

By Robert Matthews

Asked by:David Cane, Cambridge

Only around five per cent of human DNA consists of genes with known functions; the rest is referred to as ‘junk’. However, scientists are finding that this junk vital controls vital processes – such as switching specific genes on and off during development. For example, in 2006 scientists in America announced that DNA, previously regarded as junk, may control the development of your hands and feet.

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