Physicists have discovered the secret of the biological clock
You’ve probably heard that we have an internal clock, the circadian rhythm, by which the body determines when to sleep, eat, and stay awake. It runs on a 24-hour cycle, almost like a clock on the wall. But here’s the question: why doesn’t this rhythm get lost when the temperature changes around us — in summer, in winter, or even when we leave an air-conditioned office on the street? The answer was found by scientists from Japan — the team of Gen Kurosawa from RIKEN (iTHEMS), together with colleagues from Kyoto University. In a study published in PLOS Computational Biology, they used mathematical models and theoretical physics methods to explain how temperature affects gene activity, but does not disrupt biological rhythm.
The circadian rhythm is based on the cyclic switching on and off of clock genes, the synchronous accumulation and decrease of levels of mRNA (molecule) and proteins. It is customary to compare these cycles with the oscillations of a pendulum or with a smooth sinusoid.
As a rule, an increase in temperature accelerates chemical reactions: mRNA should appear faster and disappear as quickly. But a study by Gene Kurosawa and co-authors showed that it’s not just about speed, but also about the shape of the rhythm. At a higher temperature, the rise is faster, and the decline is longer, and the sine wave becomes asymmetric — attached to one side.
The theoretical predictions were confirmed in practice: in fruit flies and mice at elevated temperatures, just such a deformation of the wave pattern of gene activity was observed, while the cycle duration remained 24 hours. This deformation is a key mechanism of temperature compensation: it allows the rhythm to remain stable despite the acceleration of biochemistry. In addition, the waveform affects synchronization with the external cycle of light and dark. The stronger the distortion, the less external signals can disrupt the rhythm. This is important for adapting to jet lag and irregular lighting conditions.
The complex study opens up important perspectives, from the deep theory of biological rhythms to new approaches in the diagnosis and treatment of sleep disorders and adaptation, as well as understanding the universal principle of cycle stability in nature.
Published
July, 2025
Category
Science
Duration of reading
2—3 minutes
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