Robustness of Clocks to Input Noise

Area of Science:

• Chronobiology
• Systems Biology
• Biophysics

Background:

• Organisms utilize circadian clocks, often limit-cycle oscillators, for time estimation with a ~24-hour period.
• Alternative time-keeping mechanisms, like bacterial hourglass systems, exist and can infer time from external cues.

Purpose of the Study:

• To compare the time-telling efficiency of limit-cycle oscillators versus two types of hourglass models.
• To investigate the impact of input noise on the performance of these biological time-keeping systems.

Main Methods:

• Computational modeling of the Kai system in cyanobacteria.
• Analysis of a limit-cycle oscillator model and two hourglass models (exponential and oscillatory relaxation).
• Evaluation of system performance under varying levels of input noise.

Main Results:

• All three models (limit-cycle oscillator, exponential hourglass, oscillatory hourglass) showed similar time-telling accuracy in low-noise environments.
• In high-noise conditions, the limit-cycle oscillator demonstrated significantly superior performance compared to both hourglass models.
• This noise-dependent performance difference was also observed in the universal Stuart-Landau model.

Conclusions:

• Limit-cycle oscillators offer greater robustness and accuracy for biological time estimation in noisy environments.
• Hourglass systems, while functional, are more susceptible to environmental fluctuations.
• The findings highlight the adaptive advantages of different time-keeping mechanisms across varying biological contexts.