TY - JOUR T1 - Subharmonics and chaos in simple periodically-forced biomolecular models JF - bioRxiv DO - 10.1101/145201 SP - 145201 AU - Evgeni V. Nikolaev AU - Sahand Jamal Rahi AU - Eduardo D. Sontag Y1 - 2017/01/01 UR - http://biorxiv.org/content/early/2017/06/02/145201.abstract N2 - This paper uncovers a remarkable behavior in two biochemical systems that commonly appear as components of signal transduction pathways in systems biology. These systems have globally attracting steady states when unforced, so they might have been considered “uninteresting” from a dynamical standpoint. However, when subject to a periodic excitation, strange attractors arise via a period-doubling cascade. Quantitative analyses of the corresponding discrete chaotic trajectories are conducted numerically by computing largest Lyapunov exponents, power spectra, and autocorrelation functions. To gain insight into the geometry of the strange attractors, the phase portraits of the corresponding iterated maps are interpreted as scatter plots for which marginal distributions are additionally evaluated. The lack of entrainment to external oscillations, in even the simplest biochemical networks, represents a level of additional complexity in molecular biology, which has previously been insufficiently recognized but is plausibly biologically important. ER -