Biological Clocks, Rhythms, And Oscillations: The Theory Of Biological Timekeeping

Daniel B Forger
MIT Press, £54.95

Last year's Nobel Prize for Physiology or Medicine was awarded for discovering the genetic basis of mechanisms that underlie the control of circadian rhythms. The winners' work was originally published more than 30 years ago, and since then numerous biorhythms have been discovered acting at the molecular level.

The physiological purpose of these rhythms is fundamentally regulation. To study the overall behaviour of the clocks that maintain these regulatory mechanisms, it is essential to select suitable mathematical models. These models vary depending on the clock mechanism. So, for example, transcription regulation can be represented by at least three models depending on assumptions regarding the number of binding sites on the promoter or the interactions between the activator and repressor proteins.

The first chapters of this book introduce the principles of this mathematical modelling and then the selection of appropriate models in exemplar molecular systems. Many circadian clocks in poikilothermic organisms are temperature compensated. However, the rate of many biochemical reactions doubles with a 10°C rise in temperature. This implies that a regulating mechanism is present within these clocks to restrict any acceleration of the oscillation periods at higher temperatures.

The later chapters use simpler models to describe changes in the behaviour of oscillations close to bifurcations in the presence of noise and phase shifts, and then deal with the principles of synchrony. The final section addresses computation and analysis.

The reader is gently led through the steps in the statistics and necessary calculus. Within each chapter, there are sections that demonstrate the application of the models using examples from cutting-edge research. At the end of each chapter, there are questions to challenge the reader with self-assessment tasks. A website link to the solutions would be helpful.

This text will be a valuable reference for researchers working in chronobiology. It would also be useful for undergraduates reading mathematical biology.

Alexander Waller