1. Methods for in Vitro Evolution of Constructs Derived from Viruses. 2. Five Mutations Derived from the in Vitro Evolution. 3. Seventeen constructs from the five mutations.

The disclosure provides methods for an in vitro evolution technique to identify and characterize mutations in the non-structural genes of an alphavirus replicon that increase the strength and persistence of expression of the replicon genome. Also provided herein are in vivo methods for administering to an animal model a mutated alphavirus replicon that codes for a gene of experimental or therapeutic interest in the subgenome of the alphavirus replicon. The mutations identified herein improve the therapeutic potential of self-replicating RNA, which may have implications for cancer immunotherapy and beyond, e.g., for vaccination or gene therapy.