chapter  14
Genomes II: DNA Viruses
Pages 16

DNA viruses have from about 10 to approximately 1,000 genes with genomes ranging from a few thousand to over a million bases of DNA. Therefore, they range from viruses that are about as complex as many simple RNA viruses to those that are as complex as some Bacteria and Archaea. However, all are obligate parasites and need host cells to replicate and produce more virus particles. The Acanthamoeba Polyphaga Mimivirus (APMV) can actually be infected by another virus (a satellite virus, or virophage, called Sputnik) and, so, the line between living and nonliving is further blurred by the presence of these complex viruses that also are parasitized. It is a further indication that the progression from simple molecules through enzymatic/replicating molecules through viruses through cellular organisms is a smooth one with no absolute lines between each of the stages.