Preface/Front Matter

Abstract

The basic features of the hereditary Material, the mechanism of its readout, and much of the encoded biochemical repertoire of cells are conserved in all living organisms on our planet. This is the key to the realization that life, as we know it, descended from a common ancestor. The time from the existence of this ancestor, several billion years ago, contrasts with the time from the emergence of modern humans and language, a mere 50,000–200,000 years ago. For millennia, however, the rich diversity of life obscured appreciation of its essential unity—without scientific investigation it was not obvious that the molecular similarities between an elephant and a tree are as striking as their obvious differences. The facility to appreciate this unity followed from the development of agriculture and complex society a mere 10,000 years ago. We all are privileged to be among the first generation of life that can pose the question of its origin in meaningful molecular terms.

This third edition of The RNA World does not deal with the fascinating clash of diverse dogmas associated with different origin-of-life hypotheses formulated before the insights provided by the scientific era. Rather, it focuses on the hypothesis that RNA, acting both as hereditary information and as a catalyst, provided the basis for self-reproducing forms prior to the emergence of our modern biological world. Genetic information now is lodged in a separate storage repository, DNA, and most catalytic functions are mediated by more biochemically versatile proteins.

The second focus of this