How to control complex networks

CAMBRIDGE, Mass. At first glance, a diagram of the complex network of genes that regulate cellular metabolism might seem hopelessly complex, and efforts to control such a system futile. However, an MIT researcher has come up with a new computational model that can analyze any type of complex network - biological, social or electronic - and reveal the critical points that can be used to control the entire system. Potential applications of this work, which appears as the cover story in the May 12 issue of Nature , include reprogramming adult cells and identifying new drug targets, says study author Jean-Jacques Slotine, an MIT professor of mechanical engineering and brain and cognitive sciences. Slotine and his co-authors applied their model to dozens of real-life networks, including cell-phone networks, social networks, the networks that control gene expression in cells and the neuronal network of the C. elegans worm. For each, they calculated the percentage of points that need to be controlled in order to gain control of the entire system. For sparse networks such as gene regulatory networks, they found the number is high, around 80 percent.