Notably, viruses as vectors (mainly RNA viruses) have the potential to rearrange the genomic material, and thus, to change the domain architecture [12, 13, 14] . Studies on horizontal gene transfer focused primarily on viruses infecting bacteria and archaea (e.g., bacteriophages) [15, 16] . The co-evolution of viruses toward their hosts indicates an active crosstalk on an evolutionary time scale [17, 18, 19] .