Parts of DNA Labelled "Junk" May Be Important Switches

Can control genetic activity and may provide insight about disease transmission such as diabetes

Almost a decade after the U.S. human genome project was completed, scientists say they have mapped the underlying regulatory system that switches DNA on and off, potentially spurring a wave of new research into the molecular basis of complex diseases such as Type 1 diabetes.

Many parts of DNA previously termed "junk" by scientists are, instead, levers that control the genetic activity that can lead alternately to health or illness, according to reports published simultaneously today in the journals Science and Nature by the Encode international consortium.

Scientists previously thought that only genes, small pieces of DNA that comprise about 1 percent of the genome, have a function. The new findings show that an underlying circuitry exists in which 80 percent of the DNA code within each human cell can contribute to disease. This may be why large studies targeting gene variants haven't identified treatable causes for many complex maladies, the scientists said. The circuitry can be disrupted at several individual waypoints.