The progress of the molecular biosciences has been so enormous that a discipline studying how cellular functioning emerges out of the behaviors of their molecular constituents has become reality. Systems biology studies cells as spatiotemporal networks of interacting molecules using an integrative approach of theory (mathematics, physics, engineering), experimental biology (genetics, molecular biology, physiology), and quantitative network-wide analytical measurement (analytical biochemistry, imaging). Its aim is to understand how molecules jointly bring about life. Systems biology is rapidly discovering principles governing the functioning of molecular networks and methods to model and measure them. The application of the conceptual strength of systems sciences such as physics and engineering are opening up new ways of experimentally studying the design and functioning of molecular networks. Typically, in such studies models are used to highlight principles, design experiments, or to act in a predictive mode to specifically modify cellular behavior. In this trend article, theoretical approaches being applied in systems biology will be discussed. A number of books have recently appeared that deal with theoretical aspects of systems biology. In this article they are highlighted to facilitate the communication of systems biology to a broader audience. © 2007, Konrad Lorenz Institute for Evolution and Cognition Research.
