Experiments designed to study the evolution of self-duplicating nucleic acid molecules outside of living cells. A classic example is a study that involved the synthesis of RNA molecules using Qβ replicase and the RNA genome of Qβ phage. Serial transfer experiments were performed in which the intervals of synthesis were adjusted to select the earliest molecules completed. As the experiment progressed, the rate of RNA synthesis increased, while the product became smaller. By the 74th transfer, an RNA molecule had evolved that was only 17% of its original size and constituted the smallest known self-duplicating molecule. While it had a very high affinity for the replicase, it was unable to direct the syntheses of viral particles. Ribozymes (q.v.) have also been shown to undergo in vitro evolution. See Chronology, 1967, Spiegelmann, Mills, and Peterson; 1973, Mills, Kramer, and Spiegelmann; 1995, Wilson and Szostak.
Subjects: Genetics and Genomics.