A recombination-based model for the origin and early evolution of genetic information.

Recombination is the exchange of groups of subunits between two entities. It is argued here that this process was central to the origin of life, because it allowed for the creation of useful information from a random pool of linear polymers. The length distribution of such a pool could be broadened if these polymers, such as RNA strands, have the capability of interacting and performing a cross-strand nucleophilic attack of a hydroxy group on a phosphate. Both the formation of stable secondary structures such as stem-loops and selection for self-replication can operate to push the equilibrium length distribution of the pool to longer and more catalytically proficient oligomers. There is empirical and theoretical support for these operations. Finally, in a collection of recombining linear oligomers, the advent of short recognition sequences that favor certain interactions over others, the property of a genotypic 'self' could develop, which later can shed its collective nature and be subject to Darwinian evolution. This could have given rise to true replicase enzymes, for example.