The synthesis of a self-propagating and infectious nucleic acid with a purified enzyme.

Spiegelman's Monster, the name given to an RNA chain of only 218 nucleotides that can be reproduced by the RNA replication enzyme RNA-dependent RNA polymerase, also called RNA replicase. Spiegelman achieved the first synthesis of a biologically competent, infective viral nucleic acid. See https://profiles.nlm.nih.gov/spotlight/px/feature/monster

With I. Haruna, I. B. Holland, G. Beaudreau, and D. Mlls. Digital facsimile from PubMedCentral at this link.