Before revision: The evolution of protein-protein interactions over time has led to a complex network whose character is modular in the cellular function and highly correlated in its connectivity. The question of the characterization and emergence of modularity following principles of evolution remains an important challenge as there is no encompassing theory to explain the resulting modular topology.
After revision: The evolution of protein-protein interaction (PPI) networks are the key to the characterization and emergence of modularity following principles of evolution remains an important challenge as there is no encompassing theory to explain the resulting modular topology.