Emergence of a New Self-Replicator from a Dynamic Combinatorial Library Requires a Specific Pre-Existing Replicator

Area of Science:

• Systems chemistry
• Origin of life research
• Molecular self-replication

Background:

• Understanding the minimal molecular basis for life and early evolution remains incomplete.
• Systems chemistry investigates self-replicating molecules, but cross-catalytic effects are understudied.
• Existing research often focuses on single replicators rather than their interactions.

Purpose of the Study:

• To investigate the cross-catalyzed emergence of novel self-replicators.
• To explore the role of existing replicators in the formation of new ones.
• To understand history-dependent composition in molecular systems.

Main Methods:

• Formation of a dynamic combinatorial library from a threonine-containing peptide building block.
• Seeding the library with different macrocyclic replicators (hexamers and octamers).
• Observing the emergence of new replicators under different seeding conditions.

Main Results:

• The threonine peptide library, by itself, only formed non-replicating trimers and tetramers.
• A novel hexamer replicator composed of the threonine peptide emerged only when the library was seeded with an octamer replicator of a serine building block.
• This demonstrates cross-catalyzed emergence dependent on the presence of a specific external replicator.

Conclusions:

• A new replicator can emerge via cross-catalysis, requiring assistance from another replicator.
• The composition of emergent replicators is dependent on the system's history and introduced components.
• This study provides insights into the emergence of molecular complexity and potentially early life forms.