Abstract
Circadian rhythms of the living organisms are 24hr oscillations found in behavior, bio-chemistry and physiology. Under constant conditions, the rhythms continue with their intrinsic period length, which are rarely exact 24hr. In this paper, we examine the ef-fects of light on the phase of the gene expression rhythms derived from the interacting feedback network of a few clock genes, taking advantage of a computer simulation with Cell Illustrator. The simulation results suggested that the interacting circadian feedback network at the molecular level is essential for phase dependence of the light effects, ob-served in mammalian behavior. Furthermore, the simulation reproduced the biological observations that the range of entrainment to shorter or longer than 24hr light-dark cy-cles is limited, centering around 24hr. Application of our model to inter-time zone flight successfully demonstrated that 6 to 7 days are required to recover from jet lag when traveling from Tokyo to New York.
