Global properties of biological networks

Our inability to understand the living cell as a whole is similar to our misunderstanding of other complex networked systems such as the Internet. And it is certainly not due to a lack of knowledge about the individual elements - the genes, the proteins and the metabolites. This article discusses the most recent achievements in understanding the biological implications of the small-world and scale-free global topological properties of genetic, proteomic and metabolic networks. Most importantly, these networks are highly clustered and have small node-to-node distances. With their few very connected nodes, which are statistically unlikely to fail under random conditions, the proper functioning of these systems is maintained under external perturbations.