The 2017 Nobel Prize winners for Medicine will go to a trio of American circadian rhythm researchers, Jeffrey Hall Michael Young and Michael Rosbash, for their seminal discoveries explaining how living creatures—including plants, animals and humans—adapt their biological rhythms to align with Earth’s rotation.
Circadian rhythm basically explains why humans experience jet lag – when there is a difference between our external environment and our internal biological clocks. It also helps explain why humans sleep better in darkness. Like other species, humans possess an internal clock that adapts to day and night—a cycle rightly called circadian, from the Latin words circa meaning “around” and dies meaning “day.”
In the 1980s, the award-winning researchers specifically identified the underlying mechanisms that control fruit flies’ internal 24-hour cycles. The researchers studied fruit flies, in which a gene called period was seemingly in control of the circadian rhythm, and the insects lost that rhythm when the mutation occurred.
According to The Scientific Journal, Hall and Rosbash also discovered that a certain protein called PER, encoded by period, would accumulate during the night and degrade during the day. The importance of this work was that they found PER protein levels fluctuate over a 24-hour cycle—aligned with the circadian rhythm. They further theorized that an inhibitory feedback loop of the PER protein blocks the activity of the period gene, so the protein could prevent its own synthesis and thus regulate its own levels in a constant rhythm.
In 1994, Young furthered the understanding of circadian rhythms by explaining the occurrence of the protein that builds up in cells during the night. He discovered a second clock gene, called ‘timeless’, that encodes another protein, TIM, which is required for a normal circadian rhythm. When TIM pairs up with PER, he found, the two proteins together are able to enter a cell nucleus and block ‘period’ gene activity, closing the inhibitory feedback loop.
The Nobel laureates’ groundbreaking work has changed the world’s understanding of medicine and biology. Researchers now know our biological clocks help regulate sleep patterns, feeding behavior, hormone release, blood pressure and the body’s temperature, among other vital processes.
Rosbash received a ‘wake-up’ call from the Nobel committee about his win at 5 am local time, “I am very pleased for the fruit fly,” he said. “When the landline rings at that hour, normally it is because someone died”. The laureates also share a cash prize of USD 1.1 million dollars among themselves.
To give you a better understanding of the circadian rhythm, here are a few ways in which it affects us –
Jetlag: When you reach a different time zone compared to the one you were in, some of your organs catch up faster than others. During this adjustment period, your organs are aligned to different clocks running at different speeds. As a result, they struggle to function normally, thus affecting your body.
Mental focus: Your brain is at its sharpest at a particular time of day, but that specific time is different for everyone. New brain cells, new synapses, sleep, and attention are all regulated by the time of day, so having a set routine will ensure that they’re at their absolute best.
Nutrition: Circadian rhythms also control your hunger. Your body reacts to food differently at different times of the day. For example, at night, food converts into fat more easily than during the day.
Fertility: Your sex drive and sex hormones both have a circadian rhythm. For example, ovulation is under circadian control to happen in the early morning. According to Quartz, this was first documented when IVF was invented in France and they found women flying in from the US had lower success rates – Turns out jetlag affected their ovulation!
Aging: Finally, as you get older, your body has more trouble being in sync. This mismatch can lead to a series of age-related issues that you’d face.
