With the increasing numbers of sequenced viruses, similarity among seemingly unrelated viruses was reported. A role of the hosts as vehicles for such cases is proposed. For example, the structural similarities observed between bacterial viruses (PRD1, Bam35), Chlorella virus (PBCV-1) and adenovirus in the coat proteins, led to the proposal that all viruses are old, probably preceding the cellular life. Furthermore, it is compatible with polyphyletic virus origins, as opposed to the monophyletic origin of cellular life [10] . Still, assignment of viruses to the phylogenetic tree of life remains unresolved [11] .