The first step in decoding the genetic information of DNA is to pry apart the strands of the double helix so that a protein called RNA polymerase can wedge in between and synthesize RNA molecules. In this week's Science two groups deduce that after RNA polymerase has hooked onto a gene, it remains stationary but spools and scrunches DNA into itself. The change in distance between two fluorescent molecules affixed to the protein [green and red] told researchers where the strands of DNA would be pulled [orange and blue arrows] and where they would emerge [pink and orange dashed lines]. As the polymerase unwinds DNA it may store energy like a rubber-band-powered airplane being wound up, the researchers say.