A visualization method that combines simultaneous fluorescence immunostaining and FISH represents a powerful means to monitor and visualize DNA–protein interactions in situ. This method has been extensively used in basic chromosomal biology and in medical diagnostics related analysis due to its versatility; it is capable of analyzing the structures, functions, behaviors and abnormalities of chromatin domains, individual chromosomes or specific regions, and entire genomes or various cell populations. In this chapter, detailed protocols that can be applied to study both mitotic and meiotic chromosomes and cells are presented, along with a brief introduction of the methodology and its popular uses in the field of chromosome and genome research. Some technical considerations and possible future directions are also covered.
