In 2003 the Human Genome Project gave us all the A’s, G’s, C’s, and T’s in our DNA, but that readout told little about how those molecular components are used, controlled and organized. Last September researchers narrowed that gap between reading our genome and understanding it by cataloging the activity of most of its 3 billion letters.
The ambitious venture, called Encode (the Encyclopedia of DNA Elements), required a team of 442 scientists studying genetic activity in 147 different types of human cells. Just 1.5 percent of the genome directs the building of proteins, the molecular workhorses of our cells. The Encode team provided the first comprehensive look at the roles played by the rest. Some of the letters serve as landing spots for proteins that switch genes on and off, while others determine how DNA folds inside a cell. “Encode has fundamentally changed my view of our genome,” project leader Ewan Birney says. “It’s like a jungle in there.”
One immediate benefit is a set of new clues about diseases such as Crohn’s disease and diabetes. The Encode results also revealed that most mutations associated with disease risk lie in parts of the genome that control the activity of other genes. Ultimately, Birney sees the Encode data as an essential step toward understanding how strands of DNA get translated into a living, breathing human. “I think it’s going to take this century to fill in all the details,” Birney says. “That full reconciliation is going to be this century’s science.”