Positional information dynamics in developing embryos can be quantified through information-theoretic decomposition of mutual information between cell positions and properties over time, revealing that dynamic tissues function as information channels with capacity constrained by cell mixing, that embryos across species lose approximately 40-50% of predictive information during gastrulation through morphogenesis-structured mixing patterns, and that information-theoretic inequalities can distinguish between programmed extracellular cues and self-organizing intercellular interactions as sources of pattern generation.

During development, embryos store, transmit, and transform information to generate spatial patterns. Positional information (PI) quantifies how precisely cells form patterns at a given time, but cell motion has limited its application to static tissues. We introduce a framework for PI in dynamic tissues by decomposing mutual information between cells’ positions and properties over time into information flows contributing to PI preservation, loss and generation. These reveal information-theoretic signatures of ubiquitous developmental processes, including instruction, sorting and mixing, directly from data. Applying this framework to whole-embryo cell trajectories in Drosophila, mouse and zebrafish gastrulation, we provide local and global information-theoretic quantification of cell mixing and derive bounds on PI preservation imposed by tissue dynamics. Analyzing tissue flows as dynamical systems, we further show that morphogenesis structures mixing, preferentially preserving specific patterns. Finally, we derive inequality conditions for tracing generated PI to candidate information sources and distinguishing among alternative pattern-formation mechanisms, from programmed extracellular cues to self-organizing intercellular interactions.