Autogenesis: An Alternative Path to Molecular Information

In contrast to an RNA-first origin-of-life scenario, we describe an alternative proto-life process called “autogenesis” to explain how a molecule’s structure (for example, nucleotide sequence) can become exapted to record and convey information about other molecular relationships. No attempt is made to account for the evolution of the genetic code. Instead, we only explore the necessary and sufficient conditions for molecular information to initially evolve. Beginning with a model system described as an autogenic (that is, nonparasitic) virus, constituted only by peptides, we show how reciprocal constraints produced by self-organizing molecular interactions can become self-maintaining and then offloaded onto a nucleotide polymer like an RNA molecule. We argue that nucleotide monomers may have initially evolved as by-products of autogenesis because of their energy-transfer capacity and were preserved by polymerization when free energy would be deleterious. In polymeric form, an RNA molecule can assume both linear and “folded” 3D configurations depending on surrounding conditions. In its 3D configuration, it can serve as a catalyst by biasing the probability of specific peptide interactions due to the ways they bind to it. Because the 3D folding of an RNA polymer is largely determined by the affinities of its complementary bases, there is a high correlation between its linear nucleotide sequence and its 3D configuration. This correlation enables a replicable nucleotide sequence to correspond to a specific catalytic function and thereby become susceptible to selection for its information-conveying capacity. This provides an evolutionary scenario that accounts for the plausible de novo origin of molecular information, whereas all other current origin-of-life paradigms merely equate information with pattern replication or else just assume it as an intrinsic molecular property.