Chasing the tail: The emergence of autocatalytic networks

A ubiquitous feature of all living systems is their ability to sustain a biochemistry in which all reactions are coordinated by catalysts, and all reactants (along with the catalysts) are either produced by the system itself or are available from the environment. This led to the hypothesis that 'autocatalytic networks' play a key role in both the origin and the organization of life, which was first proposed in the early 1970s, and has been enriched in recent years by a combination of experimental studies and the application of mathematical and computational techniques. The latter have allowed a formalization and detailed analysis of such networks, by means of RAF theory. In this review, we describe the development of these ideas, from pioneering early work of Stuart Kauffman through to more recent theoretical and experimental studies. We conclude with some suggestions for future work.