One of the biggest mysteries in genetics has been solved after an international team of hundreds of scientists uncovered the secrets of “junk DNA”.
Hailed as the biggest breakthrough in genomics in a decade, the project explained how swathes of DNA once thought to have no purpose, actually form a complex “control panel” for our genes.The study is expected to lead to new medical treatments by pinpointing key areas of the genome which cause diseases such as cancer.Certain “switches” have already been linked to 100 diseases including Crohn’s disease, childhood diabetes and schizophrenia. Only one to two per cent of our genome contains genes, the parts of our DNA bearing instructions for the creation of proteins from which cells are made.
The remainder of the genome, especially areas located far away from genes, was initially thought to have no purpose and was dismissively labelled “junk DNA”.In the new project, named Encode, scientists found that 80 per cent of the “junk” region helps dictate how and where proteins are produced. In particular, they found four million areas which act like dimmer switches for individual genes, dictating how active or inactive each one is.In 30 academic papers published across three scientific journals, experts from 32 institutions throughout the world, including Britain, compiled a detailed map of four million pieces of DNA which regulate how our genes work.
In the past two decades, scientists had begun to realise that “junk” areas must have some function, because they appeared to influence our susceptibility to disease. But the researchers said they had been astonished to find how many parts of the genome were playing an active role.Dr Ewan Birney, a Cambridge scientist who helped lead the project, said: “This idea of junk DNA – we always knew must be something more than protein coding genes, things that switch them on and off. But I really was not expecting this number and density of switches. It feels like a jungle out there. It is not a neat orderly place. It is absolutely full of life.”
Mapping out how the “switches” work will enable other scientists to examine more closely how mutations in each part of the genome can lead to disease, and potentially develop new treatments, he added.In the next five years the data, published in the Nature, Genome Biology and Genome Research journals will be used to recategorise diseases, for example cancers which can often be broken down into sub-types based on their genetic profile.Longer-term goals will be to determine whether existing drugs could be effective against different conditions, and ultimately to develop new and better targeted drugs. -Telegraph
