2006 Recipient Chosen for International Prize for Biology

Dr. Serge Daan

On 7 September, JSPS's Committee on the International Prize for Biology (chaired by Dr. Saburo Nagakura, president of The Japan Academy) decided, based on the recommendation of the Prize's Selection Committee, to present the 2006 International Prize for Biology to Dr. Serge Daan, Niko Tinbergen Chair in Behavioral Biology, University of Groningen, The Netherlands. The field of specialization for the 2006 Prize is "Chronobiology."

Achievements Recognized by the Award

Conducting detailed observations and investigations using rodent behavior as an indicator, Dr. Daan elucidated the basic properties of circadian rhythm and its role in behavior expression and physiological phenomena. By formulating models based on these findings, he succeeded in explaining the underlying mechanisms of rhythmicity, thereby laying the foundations of chronobiology.

In this work, Dr. Daan conducted both empirical and theoretical analyses on virtually all the important properties of circadian rhythms and their adaptive significance. Among the questions he investigated were the mechanism by which circadian rhythm is synchronized to light-dark cycle (entrainment) and its ecological significance; the after-effects of entrainment; seasonal adaptation; and a regulatory mechanism for bimodal rhythms (those with dawn and dusk activity peaks) which involves separate morning and evening (M-E) oscillators. The five papers in which these findings were published in the Journal of Comparative Physiology in 1976 are now regarded as classics in the field of chronobiology and are required reading for every scientist who studies biological clocks. In particular, the M-E two-oscillator model proposed in these papers renders a masterful explanation of the diurnal cycle of circadian rhythms, seasonal adaptation, and photoperiodic response, so it has been highly influential in all subsequent research on the clock mechanism.

In his work on human sleep, Dr. Daan contributed to our understanding of the human sleep rhythm by demonstrating that sleep duration is determined by fluctuations in sleepregulating variables between the upper and lower thresholds of the sleep rhythm, whose range is entrained to the circadian rhythm. His research on animal hibernation changed the accepted view of a phenomenon long believed to be similar to sleep, demonstrating that hibernation is in fact a kind of sleep deprivation.

Further, Dr. Daan was one of the first researchers to focus on the ecological significance of annual cycles and related circadian rhythms from the viewpoint of ecological energetics. By analyzing the temporal organization of a predator-prey system, the kestrel and the common vole, he showed that, for both predators and prey, daily habits have survival value. In an analysis of the timing and success rate of reproduction in kestrels, he showed that reproductive timing is tuned to stored energy resources in the female. These studies made a profound contribution to understanding the adaptive significance of circadian rhythms and seasonality.

These many research breakthroughs, which have contributed greatly to the advancement of chronobiology, make Dr. Daan a worthy recipient of the International Prize for Biology.

Process of Selection

The Selection Committee composed of a chair (Dr. Motonori Hoshi, professor emeritus, Tokyo Institute of Technology) and 18 other members, including four overseas members, functioned as a sub-committee of the Committee on the International Prize for Biology. It sent out invitations for candidate nominations to Japanese and overseas universities, research institutions, academic societies and individual experts in the subject field of specialization. Altogether these comprised 1,794 mailing addresses. Sixty-eight nominations were received by the deadline. After adjustment for overlapping nominations, there were nominations for 31 individuals who reside in 14 countries spread throughout the world. Upon careful deliberation of the nominees at its first through fourth meetings, the Selection Committee decided to recommend Dr. Daan as the nominee for the 2006 Prize. Thereafter, the Committee on the International Prize for Biology formally endorsed the Selection Committee's recommendation.

Ceremony, Commemorative Lecture and Symposium

The award ceremony was convened on 20 November at The Japan Academy. This year for the first time, an afterceremony lecture open to the public was held to celebrate the award presentation on 28 November. At it, Dr. Daan offered in layman's language an introduction to chronobiology, giving the attentive public a deeper understanding of the workings of biology in people's everyday lives.

To commemorate the award to Dr. Daan, an International Prize for Biology Commemorative Symposium on Chronobiology was convened on 1-2 December at the Tokyo International Forum.

- Carried out by the General Affairs Division