Three American geneticists have been awarded the Nobel Prize for their insights into the mechanism behind the circadian rhythm, the biological clock in animals and plants that regulates daily patterns of behavior and vital functions such as the metabolism, hormone levels, sleep, and body temperature. Jeffrey C. Hall, 72, Michael Rosbash, 73, and Michael W. Young, 68, shared the Physiology or Medicine prize. Hall and Rosbash were recognized for their work at Brandeis University in Massachusetts, USA, and Young for his research at Rockefeller University in New York. By isolating genes linked to the circadian rhythm, such as the “timeless” (TIM) and “period” (PER) genes, they pioneered the establishment of direct connections between DNA and behavior. The announcement of the Medicine laureate is almost always a surprise, but for biologist Maisa Araújo, this year’s prize was not unexpected. “They have worked in close collaboration on this for years, and have produced high-quality results,” says the researcher, who returned from a two-year postdoctoral fellowship at the Rosbash laboratory in April 2017, and is now working at the Oswaldo Cruz Foundation (FIOCRUZ) in Rondônia. The Nobel Prize acknowledged the fundamental importance of the circadian cycle to the life of all organisms. Adapting to situations is not enough; predicting what will happen next is essential to survival. “There is a great advantage in using the early hours of the day to hunt or avoid being eaten,” said Anna Wedell, chair of the Nobel Committee for Physiology or Medicine.