The RNA World and the origin of life: A short history of a tidy evolutionary narrative

Although we are far from understanding how life first appeared on Earth, during the past twenty years there have been a number of major developments in origin of life studies that merit review. This is especially true of the evolutionary significance of recent discoveries of RNA biology, given the breathtaking pace at which the many roles in RNA in cellular processes and in evolution are being elucidated. The realization that the ribosome is a ribozyme and the stunning widening of the catalytic repertoire of RNA under in vitro conditions that allow the evolution of new chemical abilities has transformed current notions of the emergence and early evolution of life. The surprising ability of RNA molecules to catalyze an increasingly large number of chemical reactions has lent strong support to the possibility of the antiquity of ribozymes in the early evolution of life. Although there are many definitions of the RNA World, it is a hypothesis has gone from strength to strength, and the purpose of this chapter is to demonstrate that current ideas on the RNA World are part of a long and storied scientific perspective whose historical analysis has many lessons to teach us.