Mechanisms of DNA Virus Evolution

The mechanisms by which DNA viruses adapt and evolve over time include minor accumulated changes associated with genetic drift - such as single nucleotide changes and small insertions or deletions - as well as more substantial changes equivalent to genetic shift. The latter case is most often driven by recombination between co-replicating genomes of the same or different species, but it can also include large segmental duplications and functionally tolerated deletions. Finally, instances of genetic exchange between virus and host or between virus species - i.e., horizontal gene transfer (HGT) - have driven the evolution of DNA viruses as well as their host organisms.