Self-assembly and the origin of the first RNA-like polymers

Many hypotheses for the origin of life rely on the existence of an RNA world, a time in which RNA both stored genetic information and performed catalysis, functions that are performed by DNA and proteins, respectively, in extant biology. However, the de novo synthesis of RNA by plausible prebiotic reactions has yet to be demonstrated, leading many researchers to conclude that RNA was preceded by an informational polymer that resembled RNA, but was easier to assemble, i.e., proto-RNA. Still, the synthesis of a proto-RNA is not trivial, requiring the selection of a subset of building blocks out of a diverse prebiotic chemical inventory, and their correct coupling into a polymer. In this chapter we focus on the difficulty of selection and coupling in the de novo synthesis of RNA-like polymers and provide support for the utility of molecular midwives and reversible bonding along a template in overcoming these challenges.