Most animals give birth in spring to ensure survival of the offspring, when a moderate climate and abundant food are available. Species with a short gestation or incubation period, such as quail and chicken, are long-day breeders, and their fertile period occurs in the springtime. On the other hand, species with a gestation period around 5-6 months, such as sheep, are short-day breeders. Although seasonal breeding is a clever strategy allowing animals to survive in a changing environment, it is a rate-limiting factor in the aquaculture, poultry, and livestock industries. Thus, understanding of the mechanism of seasonal time measurement is highly relevant to animal production. We have uncovered signal transduction pathway regulating seasonal reproduction in mammals, birds and fish using comparative approach. We aim to uncover the design principles of seasonal time measurement using wild Medaka fish.

　　The circadian rhythm is an about 24-hour cell-autonomous biological oscillation observed in almost all living organisms. This rhythm regulates various physiology and behaviors such as sleep-wake cycles, hormone secretion and metabolism.
We are running another laboratory in the Institute of Transformative Bio-Molecules (WPI-ITbM) in Nagoya University. The strength of ITbM lies in the world’s top cutting-edge organic synthesis and catalysis. In the ITbM laboratory, we are trying to develop “transformative bio-molecules” that significantly improve animal production and human health by taking full advantage of this cutting-edge chemical synthesis expertise. We have identified circadian period-changing and amplitude enhancing molecules. We are currently using these molecules as a tool to uncover underlying mechanism of circadian rhythms. We are also trying to develop small molecules that improve human health and animal production.