DNA unraveled

The science of life is undergoing changes so jolting that even its top researchers are feeling something akin to shell-shock. Just four years after scientists finished mapping the human genome - the full sequence of 3 billion DNA "letters" folded within every cell - they find themselves confronted by a biological jungle deeper, denser, and more difficult to penetrate than anyone imagined.

"Science is just starting to probe the wilderness between genes," said John M. Greally, molecular biologist at New York's Albert Einstein School of Medicine. "Already we're surprised and confounded by a lot of what we're seeing."

A slew of recent but unrelated studies of everything from human disease to the workings of yeast suggest that mysterious swaths of molecules - long dismissed as "junk DNA" - may be more important to health and evolution than genes themselves.

Meanwhile, a tricky substance called RNA - for decades viewed as the lowly "messenger boy " for genes and proteins - turns out to be a big league player in cell function. It may even represent the cell's command and control...