Simple Sleepers

摘要

Joan Hendricks thought she had killed her charges. She had been sitting under a dim red light in a basement for hours, tapping on vials of fruit flies to keep the insects active. Eventually, the flies rolled around seemingly lifeless; her tapping didn't rouse them. But a couple of hours later, Hendricks, a sleep researcher who is now the dean of the University of Pennsylvania veterinary school, realized her flies were simply sacked out. "They were just so sleepy," Hen-dricks says. "They were basically dead on their little fruit fly feet." That was in the late 1990s. The experiments by Hendricks and her colleagues led to the first published description of fruit fly sleep, in 2000. A second group reported similar findings a few months later, and the drowsy insects began to usher sleep research into a new molecular age. Scientists hope the new approach will help answer a question that has baffled people for centuries: Why sleep? Sleep-deprived humans feel awful and perform poorly; rats deteriorate and die if they're kept awake for barely more than 2 weeks. But no one knows the reason. Now, arguing that most organisms slumber much as humans do, a growing number of sleep researchers are welcoming fruit flies, zebrafish, and roundworms-classic simple animal models-into their labs. Already, these creatures, with their easy-to-study genomes and simple nervous systems, have yielded new evidence for how sleep maintains the brain and metabolism. They've also revealed genes that regulate sleep-including a fly gene called sleepless, described on page 372.