Preface/Front Matter

Abstract

We are all fascinated with our origins. Among the diverse human societies on earth there is a wonderful richness of explanations—the Haida of Vancouver Island originating from small beings who crawled out of a clam shell onto the back of a raven to be carried to his wonderful land—the Aranda of Australia emanating as bandicoots from the armpits and navel of the “great father”—or the Yanomamo of Brazil coming from drops of blood dripping from a wound in the belly of the moon. But what was the origin of replicating molecules, those special molecules that ultimately gave rise to all extant life on earth?

Replicating the hereditary DNA molecules in all contemporary organisms requires protein catalysts. Early evolution of this mechanism poses the obvious dilemma of how to generate proteins without nucleic acid templates and how to replicate nucleic acids without protein catalysts. The notion that prebiotic evolution depended on RNA replication has intrigued many, since the early suggestions by Woese, Orgel, and Crick. However, even those of us especially interested in the current functions of RNA have been surprised by the richness of apparent “relics” from the RNA World that have been discovered. The stimulus for a new wave of interest in the RNA World came from the discovery of RNA molecules with catalytic activity. RNA can be both an informational molecule and a catalyst. Even natural catalytic RNAs, or ribozymes, can promote nucleotide joining reactions that could be a first step toward self-replication, and RNAs