Abstract EANA2025-16

The origin of molecular organization in prebiotic environments is a foundational question in studies of abiogenesis and the emergence of life. The RNA World hypothesis traditionally proposes sequence-based replication and templating as early mechanisms for information storage and evolution [1,2]. Alternative approaches suggest that compositional information and non-genetic molecular interactions may have played a critical role in the earliest stages of self-organization [3,4]. One way to approach this is by modeling networks of interacting molecules where affinity and catalytic influence govern the emergence of structure. Following this line of investigation, the present work asks if increasing the system size, by increasing the molecular variety, can give rise to increased variety of self-replicators, shedding light on the potential for open-ended diversity in prebiotic chemical environments.  

To tackle this question, networks of molecules modeled as directed weighted graphs were studied. These networks represent the interactions among distinct molecular types, where nodes correspond to individual molecules and edges are the affinities between those molecules. To analyze the structural organization within these networks, a community detection algorithm is applied to identify densely interconnected groups of nodes. These groups are interpreted as spontaneously emerging molecular assemblies or "compositional communities.”. Previous work has found that these communities serve as analogs for self-assembled molecular aggregates that are able to replicate [5]. We examined the relationship between network size and the resulting number of detected communities, by systematically increasing the number of nodes (i.e. increasing the number of distinct molecules in the system). We find a linear correlation between the number of nodes and the number of detected communities, suggesting that the model exhibits an open-ended capacity for the number of compositional communities, i.e. species. This scaling behavior indicates that as the diversity of interacting molecules increases, the system naturally gives rise to an increasing number of distinct self-replicating compositional assemblies.

The implications of this work extend to theories of compositional inheritance, modularity in chemical systems, and the emergence of complexity from simple interaction rules. By quantifying how structural complexity scales with molecular diversity, the model contributes to our understanding of how large-scale organization can emerge spontaneously in chemical networks.

 

Acknowledgements 

Financial support from Fundação para a Ciência e a Tecnologia (FCT) is acknowledged by Z.M. (project ORIGINS, 2022.05284.PTDC), O.M. (2023.05971.CEECIND), CQE (projects UIDB/00100), and IMS (project LA/P/0056/2020).

 

References

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