When it comes to regeneration, some animals are capable of amazing feats. If you cut off a salamander’s leg, it will grow back. When threatened, some geckos drop their tails to distract their predator, only to regrow them later.

Other animals take the process even further. Planarian worms, jellyfish, and sea anemones can actually regenerate their bodies after being cut in half.

Led by Assistant Professor of Organismic and Evolutionary Biology Mansi Srivastava, a team of researchers is shedding new light on how animals pull off the feat, along the way uncovering a number of DNA switches that appear to control genes for whole-body regeneration. The study is described in a March 15 paper in Science.

Using three-banded panther worms to test the process, Srivastava and Andrew Gehrke, a postdoctoral fellow working in her lab, found that a section of noncoding DNA controls the activation of a “master control gene” called early growth response, or EGR. Once active, EGR controls a number of other processes by switching other genes on or off.

“What we found is that this one master gene comes on [and activates] genes that are turning on during regeneration,” Gehrke said. “Basically, what’s going on is the noncoding regions are telling the coding regions to turn on or off, so a good way to think of it is as though they are switches.”

For that process to work, Gehrke said, the DNA in the worms’ cells, which normally is tightly folded and compacted, has to change, making new areas available for activation.

“A lot of those very tightly packed portions of the genome actually physically become more open,” he said, “because there are regulatory switches in there that have to turn genes on or off. So one of the big findings in this paper is that the genome is very dynamic and really changes during regeneration as different parts are opening and closing.”

Before Gehrke and Srivastava could understand the dynamic nature of the worm’s genome, they had to assemble its sequence — no simple feat in itself.

“That’s a big part of this paper,” Srivastava said. “We’re releasing the genome of this species, which is important because it’s the first from this phylum. Until now there had been no full genome sequence available.”