Abstract
The molecular evolution by replicase (RNA-dependent RNA polymerase) was attempted for generating new nuclease-resistant RNAs, which realizes a cell free Darwinian molecular evolution. The Qβ replicase replicates genome RNA of Qβ virus, and additionally it can also synthesize other small RNAs using “minivaliant” as a template. With the aid of Spiegelman's serial trasfer method, which is a step by step molecular evolution system in a laboratory by RNA proliferation with frequent mutation using Qβ replicase, high concentration ribonuclease T2-resistant fragments of RNA could he obtained.
