Mobile genetic elements as natural tools for genome evolution.

Transposable elements (TEs) are ubiquitous components of all living organisms, and in the course of their coexistence with their respective host genomes, these parasitic DNAs have played important roles in the evolution of complex genetic networks. The interaction between mobile DNAs and their host genomes are quite diverse, ranging from modifications of gene structure and regulation to alterations in general genome architecture. Thus over evolutionary time these elements can be regarded as natural molecular tools in shaping the organization, structure, and function of eukaryotic genes and genomes. Based on their intrinsic properties and features, mobile DNAs are widely applied at present as a technical "toolbox," essential for studying a diverse spectrum of biological questions. In this chapter we aim to review both the evolutionary impact of TEs on genome evolution and their valuable and diverse methodological applications as the molecular tools presented in this book.