New hope in disease fight as theory of ‘junk’ DNA debunked

The findings, reported in some 30 research papers, show that around 80 per cent of the genetic code is actively involved in keeping life going.

A team of more than 400 scientists from 32 laboratories around the world identified four million “switches” that determine whether genes are turned on or off.

In future, scientists hope the findings will lead to a deeper understanding of numerous diseases and help them devise more effective diagnostic tools and treatments.

Until recently large amounts of the human genetic code, or genome, were dismissed as “junk” – DNA sequences that had no function.

Experts began to realise that junk DNA might have a useful regulatory role only as recently as the 1990s. But even 10 years ago, when the Human Genome Project mapped the first definitive blueprint of the “book of life”, much of the genome was thought to be junk.

Now scientists know that almost every fragment of DNA has a purpose.

Dr Ewan Birney, chief analysis co-ordinator on the Encyclopedia of DNA Elements project, known as Encode, said: “We found that a much bigger part of the genome is involved in controlling when and where proteins are produced, than in simply manufacturing the building blocks.”