Controlling Peak Sharpness in Multimodal Biomolecular Systems via the Chemical Fokker-Planck Equation

Abstract

Intracellular biomolecular systems exhibit intrinsic stochasticity due to low molecular copy numbers, leading to multimodal probability distributions that play a crucial role in probabilistic differentiation and cellular decision-making. Controlling the dispersion of multimodal probability distributions in biomolecular systems is critical for regulating stochastic behavior, robustness, and adaptability. However, modifying system parameters to adjust dispersion often affects peak positions, potentially altering a desired phenotype or even fundamental behavior in a genetic pathway. In this paper, we establish a theoretical framework that enables independent control of dispersion while preserving peak positions and modality using the Chemical Fokker-Planck Equation (CFPE) and sharpness, a measure of probability concentration around individual peaks. By analyzing the steady-state solution of the CFPE, we derive explicit conditions under which peak sharpness can be tuned monotonically without changing peak positions or modality. We validate our approach through Monte Carlo simulations on a bimodal chemical system, demonstrating effective dispersion control while maintaining structural stability. This framework provides a systematic approach for designing biomolecular systems with tunable stochastic properties, contributing to advancements in synthetic biology and probabilistic cellular regulation.