What is junk DNA?

22nd July 2009

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.