Getting a handle on RNA virus recombination

Abstract

Most viruses have RNA genomes. We must understand how they generate diversity so we can anticipate and respond to the arrival of new strains or entirely new viruses. Owing to the high error rate of RNA-dependent replication, RNA viruses exist as heterogeneous populations of molecules known as quasispecies[1]. The advantage of quasispecies to the virus is that, as selection pressures change, a fit genome might already exist in the quasispecies population or can evolve rapidly. The disadvantage of the high error rate is that accumulation of too many mutations is damaging[1]. However, these genetic defects can be rescued by recombination with other molecules in the quasispecies that have functional genes[2]. Furthermore, by recombination, a virus can suddenly acquire entirely new traits (whole genes) in one step.