Membrane information organization at the origin of life: From interfaces to informational bodies.

Membranes are usually treated as passive containers in origin-of-life models, confining prebiotic chemistry, buffering diffusion, and sustaining gradients. Here, we argue that early membranes provided the physical substrate for candidate informational bodies: boundaries whose physical properties can stabilize, store, and select patterns of interaction with the environment. Within the Membrane Information Organization (MIO) framework, we place protocells in a low-dimensional organizational space defined by a triplet of body parameters: boundary strength, memory, and identity persistence. These parameters quantify sustained inside-outside asymmetry, history dependence beyond instantaneous forcing, and the reproducibility of organizational types across growth-division cycles. In this view, the origin of life is cast as a transition in which amphiphile-based vesicles cross jointly calibrated thresholds in boundary strength, memory, and identity, thereby becoming candidate selectable units prior to fully genetic inheritance. We outline how these quantities can be estimated in fatty-acid and hybrid protocells using microfluidic driving, Laurdan-based lipid-order imaging, curvature reconstruction, and fluorescent internal reporters, and how they can be incorporated into computational models of protocell ecologies. This boundary-centered perspective complements RNA-world, metabolism-first, and autonomy-based scenarios by specifying membrane-level conditions under which replicators, reaction networks, and proto-metabolisms can become evolutionarily stable. The result is not a new chemistry, but a concrete measurement language for identifying when a membrane ceases to be "just a vesicle" and enters a candidate minimal evolvable informational-body regime.