As more and more RNA viruses have been sequenced, it has become clear that RNA
recombination has been a major force in the evolution of RNA-containing viruses.
Recombination has led to the origin of new families and genera of RNA viruses and to the
origin of new variants within a genus. Recombination also leads to the production of
defective-interfering (DI) RNAs, which have been important tools in the study of cis-acting
regulatory sequences in RNA viruses. Recombination is thought to occur when a viral RNA …