Scientists receive 2017 Nobel Prize for work on the circadian rhythm

Hayley Roper
Research Assistant

Three U.S. scientists were awarded the 2017 Nobel Prize in Physiology and Medicine for their collaborative work in uncovering the role of a gene that aligns the body’s circadian rhythm, or internal clock, with the Earth’s revolutions.

It’s been known for a while that living organisms have an internal clock that helps the body anticipate and adapt to the external environment. But how this works was unclear. In the 1970s, scientists identified a gene that controls the body’s internal clock. They named this gene period. This year’s Nobel winners, Michael Rosbash, Jeffrey C. Hall and Michael W. Young, succeeded in isolating period in fruit flies. By isolating period, they could discover how this gene directly influences the circadian rhythm. They discovered that period produces the protein PER, which fluctuates over the 24-hour sleep-wake cycle. PER builds up overnight and decreases during the day. Fruit flies with mutated period genes did not have this 24-hour circadian rhythm. Young later discovered two other genes that work to regulate the period gene and the production of the PER protein.

The body’s internal clock regulates various physiological processes throughout the 24-hour day. Such processes include body temperature, metabolism, hormone release, sleep, and blood pressure. For example, our body clocks are responsible for regulating the release of melatonin (“sleep hormone”) in the evening and releasing the highest levels of cortisol (“stress hormone”) in the morning upon awakening.

This prize recognizes the importance of understanding the circadian rhythm. The body’s circadian rhythm is closely linked to health and disease. Short term misalignment between the body’s internal clock and the external environment, such as jetlag, can have temporary effects on our wellbeing. Chronic misalignment has been associated with increased risk of diseases, such as diabetes.

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Image credit: Mattias Karlén. The Nobel Committee for Physiology or Medicine.