Katherine Pollard, now at the Gladstone Institute, has done most, over the last decade, to research and identify small non-coding regions of the humane genome that have evolved very rapidly since the split from the last common ancestor with chimpanzees. Hence they are called human accelerated regions or HARs. In this superb piece for The Scientist she gives an overview of the field and its history. Pollard, to date, only knows the function of one or two HARs – HAR1, for instance is involved in normal brain development through its role as enhancer to the genes that control brain growth. It is likely that many or most of the HARs already identified will be found to be important because they act as gene regulators and enhancers. As such, far from being junk DNA, they probably have vital roles, not only in what sets us apart from the other higher primates, but in normal human development – and, if things go wrong, human disease processes.