Biological networks seem to show an inherent simplicity: They contain only very few of the possible interaction patterns. These patterns are called network motifs. We will present theoretical and experimental studies on the dynamical functions of network motifs in the transcription network of the bacterium E. coli. We will also discuss how motifs and modularity in the network may have evolved.
R Milo, S Shen-Orr, S Itzkovitz, N Kashtan, D Chklovskii & U Alon, Network Motifs: Simple Building Blocks of Complex Networks Science, 298:824-827 (2002).
Erez Dekel and Uri Alon, Optimality and evolutionary tuning of the expression level of a protein. Nature, 436, 7050, 588-922 (2005).