1 Systems Biology: Toward System-level Understanding of Biological Systems

Systems biology is a new field in biology that aims at system-level understanding of biological systems. While molecular biology has led to remarkable progress in our understanding of biological systems, the current focus is mainly on identification of genes and functions of their products which are components of the system. The next major challenge is to understand at the system level biological systems that are composed of components revealed by molecular biology. This is not the first attempt at system-level understanding, since it is a recurrent theme in the scientific community. Nevertheless, it is the first time that we may be able to understand biological systems grounded in the molecular level as a consistent framework of knowledge. Now is a golden opportunity to uncover the essential principles of biological systems and applications backed up by indepth understanding of system behaviors. In order to grasp this opportunity, it is essential to establish methodologies and techniques to enable us to understand biological systems in their entirety by investigating: (1) the structure of the systems, such as genes, metabolism, and signal transduction networks and physical structures, (2) the dynamics of such systems, (3) methods to control systems, and (4) methods to design and modify systems for desired properties. This chapter gives an overview of the field of systems biology that will provide a system-level understanding of life