We found that most of the viral proteins that potentially originated from host sequences are significantly shorter and contain fewer domains. Furthermore, we propose that the sequence refinement by the virus is a dynamic process. The inter-domain linkers (e.g., sequences connecting domains, but excluding the amino-and carboxyl tails) are significantly short, relative to other related proteins ( Figure 6 ). The viral proteins act in the cell according to a finite number of strategies. The simpler domain composition of these viral proteins is sufficient for the utilization of functional mimicry. Currently, we are expanding the analysis by identifying short peptides in viral proteomes that serve as competition agents for neutralizing critical cellular functions.