Study Reveals How Temperature Influences the Biological Clock

A team led by Gen Kurosawa at the RIKEN Center for Interdisciplinary Theoretical and Mathematical Sciences (iTHEMS) has identified a key mechanism by which the biological clock maintains its 24-hour rhythm despite fluctuations in temperature. The study, published in PLOS Computational Biology, used theoretical physics to explore how gene activity adapts to external conditions.

Our biological clock relies on cyclic patterns of mRNA levels, generated by genes that switch on and off rhythmically. These fluctuations resemble a sine wave, rising and falling predictably. However, since chemical reactions typically accelerate with heat, it was previously unclear how such stability is preserved as temperatures change.

By applying a technique from physics known as the renormalization group method, Kurosawa and his team analyzed the dynamics behind mRNA rhythms. They found that while temperature changes cause mRNA levels to rise faster and fall more slowly, the overall cycle length remains unchanged. This alteration in the cycle’s “shape”—referred to as waveform distortion—helps maintain consistent timing.

To confirm their theoretical results, the researchers studied data from fruit flies and mice. These organisms displayed the predicted asymmetrical waveform shifts at higher temperatures, supporting the idea that waveform distortion is essential for temperature compensation in the internal clock.

The researchers also found that these distortions impact how the biological clock responds to environmental cues like light and dark. Greater distortion leads to less influence from such external signals, a finding observed in both flies and fungi.

“Our findings show that waveform distortion is a crucial part of how biological clocks remain accurate and synchronized, even when temperatures change,” says Kurosawa. The team hopes future research will uncover the molecular causes of these distortions and how they may vary by species, age, or individual traits.

“In the long term,” Kurosawa notes, “the degree of waveform distortion in clock genes could be a biomarker that helps us better understand sleep disorders, jet lag, and the effects of aging on our internal clocks. It might also reveal universal patterns in how rhythms work—not just in biology, but in many systems that involve repeating cycles.”