Life 2.0

Gerald Joyce explores attempts to reconstruct features of RNA-based life in the laboratory. Under the RNA world hypothesis, early organisms used RNA to store information and catalyze replication before the emergence of DNA genomes. Directed evolution has produced RNA enzymes that copy diverse templates, synthesize structured and catalytic RNAs, and amplify short templates in an RNA-catalyzed analogue of the polymerase chain reaction. A variant can make DNA from an RNA template, suggesting a possible route between RNA and DNA genomes. Joyce also describes cross-chiral enzymes that synthesize RNA of opposite handedness and can assemble their own enantiomers from fragments. The lecture examines these complementary approaches to replicating functional RNA, their relevance to the origins of life, and potential diagnostic and clinical applications.