[Fundamental aspects of synthetic biology].

Synthetic biology is an emerging interdisciplinary research field. By designing and constructing new or re-designing the existing natural systems, it confers them novel functions, which do not exist in nature. Owing to the predictability and controllability, synthetic biology attracts more and more interest from biologists, physicists, and engineers. Synthetic biology approaches not only can be widely used for biotechnological applications but also can be used to study complex biological systems to address fundamental questions. Here, we reviewed the recent studies following the concept of "build-to-understand", particularly, the studies to understand intracellular network structure, cell physiology, the behavior of multicellular populations, and ecosystems.