Self-Sustained Replication of an RNA Enzyme Tracey A. Lincoln and Gerald F. Joyce Departments of Chemistry and Molecular Biology and the Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA. Abstract: An RNA enzyme that catalyzes the RNA-templated joining of RNA was converted to a format whereby two enzymes catalyze each other’s synthesis from a total of four oligonucleotide substrates. These cross-replicating RNA enzymes undergo self-sustained exponential amplification in the absence of proteins or other biological materials. Amplification occurs with a doubling time of about one hour, and can be continued indefinitely. Populations of various cross-replicating enzymes were constructed and allowed to compete for a common pool of substrates, during which recombinant replicators arose and grew to dominate the population. These replicating RNA enzymes can serve as an experimental model of a genetic system. Many such model systems could be constructed, allowing different selective outcomes to be related to the underlying properties of the genetic system. Citation: T. A. Lincoln and G. F. Joyce, Science, 2009, DOI: 10.1126/science.1167856 http://www.rsc.org/chemistryworld/News/2009/January/09010901.asp Isn't that exciting?