The biotech community is buzzing with the recent news that a trio of American geneticists have received the 108th Nobel Prize in Physiology or Medicine for their research, which revealed the molecular mechanisms that control the circadian rhythm. In other words, they shed light on what has become popularly known as the “body clock”.
Jeffrey C. Hall, Michael Rosbash, and Michael W. Young conducted the majority of this research, which earned them the Nobel Prize in October 2017 (Hall and Rosbash worked collaboratively at Brandeis University, and Young worked independently at Rockefeller University). Up until that point, scientists were aware that plants and animals, including humans, had some kind of internal timekeeping device that helped them sync up their biological rhythm—things like sleeping and eating patterns and changes in body temperature—with the rhythm of the day governed by the Earth’s rotation, but no one knew exactly how this inner device worked.
Genes play a critical role
What Hall, Rosbash, and Young discovered through their work with fruit flies was the critical role that genes play in setting this “clock.” Their major discovery was that a particular gene controlled circadian behavior. This gene, known as the “period” gene, operates on a 24-hour cycle, encoding a protein within cells at night that then degrades over the course of the day. When there is a mismatch between this internal clock’s cycle and the external environment—jet lag is one of the most common examples of this phenomenon—the well-being of the organism can be negatively impacted.
This work is not only of significant value in helping us to increase our understanding of the mechanisms of life, but it also has some important implications in the sphere of human disease. For example, health research studies have demonstrated that when our circadian rhythms are interrupted over a prolonged period of time, such as through shift work, people are at an increased risk for cancer, metabolic disorders, and neurodegenerative diseases. Understanding how to work with and alter this out-of-kilter clock could greatly help us to improve human health. Similarly, many drugs that are currently on the market function optimally when they are taken at exactly the right time. Understanding how to identify what that right time is could have an important influence on the efficacy of treatment.
To understand more about the trio’s Nobel Prize-winning research, read on to learn more interesting facts about circadian rhythms.
What are circadian rhythms?
“Circadian rhythms” is the term for the cycle of physical, mental, and behavioral changes that most living things—including animals, plants, and many minuscule microbes—go through on a daily basis. An organism’s circadian rhythms are primarily responsive to changes in light and darkness in their environment. For instance, the clearest example of a light-related circadian rhythm is the practice of sleeping at night and being awake during the daytime. “Chronobiology” is the term for the study of circadian rhythms.
What are biological clocks?
Biological clocks are the innate timing devices found in nearly every tissue and organ of an organism. These timekeepers (the “period” gene discovered by Hall, Rosbash, and Young) are composed of proteins that interact with living cells all throughout the body. Note that biological clocks are not the same thing as circadian rhythms. Rather, biological clocks are what produce circadian rhythms and regulate the cyclical timing of those rhythms.
What is the master clock?
With so many biological clocks found in an organism’s tissues and organs, it’s important to have some way of centrally controlling and regulating them. This is the function of the master clock: in humans, this is a special group of roughly 20,000 neurons that form a structure called the suprachiasmatic nucleus, which is located in the hypothalamus (an area of the brain). It is this structure that coordinates all of the biological clocks in the human body.
Does the body make its own circadian rhythms?
While there are some natural factors within the body that produce circadian rhythms, they are primarily affected by signals from the external environment, with the main influence being daylight. Changes in daylight exposure can have the effect of turning on or off those genes that control biological clocks’ molecular structure.
Do circadian rhythms impact human health and bodily function?
Circadian rhythms influence a whole host of human behaviors and functions, including sleep-wake cycles, the release of hormones, eating habits and digestion, and body temperature. When biological clocks run fast or slow, the circadian rhythms and functions they influence can be disrupted.
How is research into circadian rhythms conducted?
To learn about circadian rhythms, scientists can study humans or other organisms that have similar biological clock genes: fruit flies and mice are two of the most common study subjects. To conduct their experiments, researchers altered the periods of light and dark in the subject’s environment, then looked at how those modifications affected gene activity or other molecular signals.