Comparative genomics of hepatitis A virus, hepatitis C virus, and hepatitis E virus provides insights into the evolutionary history of Hepatovirus species

Wassenaar, Trudy M.; Jun, Se-Ran; Robeson, Michael; Ussery, David W.

Although no sequence similarity is detected between the various virus species compared here, in combination the presented data make it plausible that an ancestor virus of HAV and other hepatoviral species was an insect virus, with a codon use adapted to that host, whose signature is still visible in current HAV genome. We consider it possible that a blood-sucking insect such as triatomes, which feeds on mammals, may have been the source for a virus crossing host species. Alternatively, a host jump may have taken place in the gut of insectivorous bats. More speculative is the possibility that in a long evolutionary past all these virus species may have originated from bacteriophages that propagated in Gram-negative AT-rich bacteria, with which they still share codon preference and amino acid frequency.