In vitro synthesis of an infectious mutant RNA with a normal RNA replicase.

When purified Qbeta-RNA replicase is presented alternately with two genetically different Qbeta-RNA molecules, the RNA synthesized is identical to the initiating template. The results establish that the RNA is the instructive agent in the replicative process and hence that it satisfies the operational definition of a self-duplicating entity. The data also eliminate alternative explanations which do not involve self-propagation of the input RNA. An opportunity is now provided for studying the genetics and evolution of a self-duplicating nucleic acid molecule under conditions permitting detailed control of environmental parameters and chemical components.