For few instances, a support exists for viruses that hijacked sequences from the host. Among Class I viruses (Table 1 ) the shared functions include interlukin-10 (IL-10) (Figure 2 ), beta-1,6-Nacetylglucosaminyltransferase (b1,6GnT) ( Figure S1 ) and Ubiquitin. The b1,6GnT and IL-10 are found exclusively in metazoa and the multicellular eukaryotic branch. The key features and the functional amino acids are conserved in the viral and the corresponding mammalian proteins (Figure 2A , Figure S1 ). Indeed, in human cells lacking b1,6GnT gene, the Bovine herpesvirus 4 (BoHV-4) sequence fully recovered the missing enzymatic activity [40] .