How a vital DNA protection protein complex adapts to new threats without compromising its essential functions

In Lewis Carroll's "Through the Looking-Glass," Alice is stuck in a never-ending race with the Red Queen yet never gains a lead. "It takes all the running you can do to keep in the same place," the Queen says. "Though we typically use this metaphor to describe evolutionary arms races between hosts and parasites or hosts and pathogens, the "Red Queen Hypothesis' also characterizes the ongoing battles within our genome," says Mia Levine, a biologist at the University of Pennsylvania.