Beyond Molecular Snapshots: Regulatory Trajectories in Dynamic Epigenetic Regulation.

Epigenetic regulation is commonly interpreted through molecular markers measured at discrete timepoints. While such approaches have generated important biological insights, they primarily provide static representations of regulatory states and may therefore capture only a limited component of dynamic biological processes. Emerging evidence from chromatin biology, transcriptional regulation and genome organisation suggests that biological regulation unfolds through continuously evolving interactions across multiple molecular layers. This article presents a biological hypothesis and conceptual framework proposing that epigenetic regulation may be more fully understood through dynamic regulatory trajectories rather than isolated molecular states. The framework conceptualises regulatory states as multidimensional configurations composed of interacting molecular layers and proposes that successive observations form longitudinal trajectories that may contain biologically meaningful information not fully captured by single-timepoint measurements. To formalise this concept, we introduce a set of formal representations describing regulatory states, state transitions and longitudinal regulatory trajectories. These representations are not intended as experimentally validated mathematical laws but as a computational formalisation of the framework's underlying assumptions. The framework therefore generates a testable proposition: in defined biological contexts, trajectory-derived features should provide information beyond that available from the most recent molecular state alone.