Chemical Fueling Enables Molecular Complexification of Self-Replicators**

Unravelling how the complexity of living systems can (have) emerge(d) from simple chemical reactions is one of the grand challenges in contemporary science. Evolving systems of self-replicating molecules may hold the key to this question. Here we show that, when a system of replicators is subjected to a regime where replication competes with replicator destruction, simple and fast replicators can give way to more complex and slower ones. The structurally more complex replicator was found to be functionally more proficient in the catalysis of a model reaction. These results show that chemical fueling can maintain systems of replicators out of equilibrium, populating more complex replicators that are otherwise not readily accessible. Such complexification represents an important requirement for achieving open-ended evolution as it should allow improved and ultimately also new functions to emerge.

Automated summary

Research has shown that in systems of self-replicating molecules, simple and fast replicators can be replaced by more complex and slower ones, with the latter being more proficient in catalysis. The use of chemical fueling can maintain replicator systems out of equilibrium, leading to the emergence of more complex replicators that enable open-ended evolution.