EXPERIMENTAL TESTING OF THEORIES OF AN EARLY RNA WORLD

This chapter explains experimental testing of theories of an early RNA world. The RNA world hypothesis provides a convenient focus for new experiments that not only test its validity but also fundamentally advance the knowledge of nucleotide chemistry and RNA catalysis. Several critical experiments fully establish (or eliminate) the idea that the forebears of modern life were replicating RNA molecules. Experiments can discern (1) whether the precursors of an RNA world—ribonucleotide monomers and oligomers—can be synthesized under conditions similar to those that existed in the prebiotic environment; (2) whether ribozymes can catalyze template-directed replication; and (3) whether ribozymes can catalyze a range of reactions similar to that of protein enzymes. Advances in nucleic acid amplification technologies have made possible the isolation and engineering of new ribozyme activities. © 1993