Departure from randomness: Evolution of self-replicators that can self-sort through steric zipper formation

Darwinian evolution of self-replicating entities most likely played a key role in the emergence of life from inanimate matter. For evolution to occur, self-replicators must (1) have structural space accessible to them, (2)occupy only part of it at any time, and (3) navigate it through mutation and selection. We describe a systemof self-replicating hexameric macrocycles formed upon the mixing of two building blocks and occupying asubset of possible sequences. Specific interactions, most likely through steric zipper formation, favor a hexamer sequence where the two blocks alternate. Under different replication-destruction regimes, distinct replicator mutants are selected. With non-selective destruction (via outflow), the fastest replicators dominate.With chemically mediated, selective destruction, a mutant that balances replication speed and resistanceto reduction by steric zipper formation becomes dominant. This system demonstrates a rudimentaryform of Darwinian evolution, where replicators adapt to changing selection pressures through mutationand selection.