ABSTRACT
Chemical genetics is the science which takes the small molecular compounds as tools to solve the genetics problems or to disturb/adjust normal biological process so as to find out protein functions. Because the small molecules have the diverse chemical characters and the ability to identify the target proteins, they also can be filtrated on the basis of phenotype. So the methods of chemical genetics have been applied in almost all of the researches on biology and medicine. In this paper, the methods to acquire small molecular compounds are introduced. The enormous progress achieved in the field of combinatorial chemistry, which has allowed the rapid production of a large number of chemically diverse molecules, is an important prerequisite to make chemical libraries available to academic researchers. And the applications of the compounds in early embryo development, cell differentiation, on-set and course of disease are discussed, too. The application of small molecules has an enormous impact on our understanding of cell biology. There are many examples where small molecules, in combination with genetic screens, have facilitated the dissection of complex cellular processes.