In other words: Just like people, there were ‘early risers’ and ‘night owls’ and long sleepers and short sleepers among the fruit flies. Some flies had unusually long circadian periods-up to 31 hours-while others had extremely short circadian periods of 15 hours. In addition to finding this treasure trove of clock-related genes, Harbison’s group also found that the circadian patterns among the flies were highly variable, and that some of the genes code for variability in the circadian clock. Many of the genes appear to be associated with nerve cell development-not surprising, she said, given the wide-ranging impact of circadian rhythms on biological processes. In recent studies using a natural population of flies, Harbison’s group estimates that there are more than 250 new genes associated with the circadian clock, among the largest number identified to date. Previous studies by other researchers had identified approximately 126 genes for circadian rhythms in fruit flies. In fact, the genes involved in mammalian circadian rhythms were first identified in flies.” “They both have biological rhythms of about 24 hours. “The clock mechanisms regulating circadian rhythm in humans and fruit flies are remarkably similar,” Harbison said. While this little fly may seem like an unlikely choice, it turns out to be an appropriate stand-in for humans. To explore this line of research more deeply, Harbison is working with a favorite laboratory model of sleep researchers: Drosophila melanogaster, the common fruit fly. Now, thanks to Harbison and her research team, new insights into why some people experience longer or shorter periods of wakefulness or sleepiness than others-and what it might mean for a host of health conditions-could be on the horizon. And a recent study by researchers in France found that heart surgery is safer in the afternoon than in the morning, a phenomenon they attribute to the body’s circadian clock having a better repair mechanism in the afternoon than in the morning. Some studies have shown a link between circadian rhythm changes and cancer. For example, long-term night shift work has been associated with an increased risk of high blood pressure, obesity, and heart disease. “Quietly, this clock influences our body and our health in ways that are just now being understood.”įor sure, the studies are slowly unfolding. Photo credit: Yazmin Serrano Negron, NHLBI.“We all ‘dance’ to the circadian rhythm,” said Susan Harbison, Ph.D., an investigator in the NHLBI’s Laboratory of Systems Genetics, who is among an elite cadre of scientists studying the complex genetics of the biological clock. Susan Harbison displays a device used to record sleep and activity in fruit flies. These researchers say these genes could hold the key to a new understanding of a wide range of health conditions, from insomnia to heart disease, and perhaps pave the way for new treatments for them. Now a team of NHLBI researchers is working to change that with the discovery of scores of new genes they say have a profound impact on the circadian rhythm. Yet, for all these advances, scientists still know relatively little about the clock’s genetic underpinnings. Since their discovery researchers have come to know that the circadian clock affects not just sleep, but hormone production, eating habits, body temperature, heart rate, and other biological functions. For this game-changing finding, the trio recently was awarded the 2017 Nobel Prize in Physiology or Medicine. That’s the 24-hour internal body clock which controls your sleep/wake cycle.Ĭircadian rhythms have long fascinated researchers-decades ago three of them marked a critical milestone when they discovered the molecular components behind that mysterious timing cycle. If you feel energized or tired around the same time each day, or routinely get up early or stay up late-the familiar ‘early riser’ or ‘night owl’ syndrome-you are witnessing, in real time, your circadian rhythm at work.

Might lead to better understanding of sleep disorders, heart disease, and more

Dancing line clock