ABSTRACT
The cytogenetics l aboratory has witnessed major advances in diagnostic and prognostic capability in the past decade with the use of molecular cytoge netics . The technique of fturoscence in situ hybridization (FISH), a hybrid of cytogenetics and molecular biology, has increased the resolution and ap plication of cytogenetics ( 1 ) . The availability of quality-controlled DNA probes from commercial sources has expedited the clinical use and accep tance of these tests . FISH is a technique that allows the detection of DNA sequences on metaphase chromosomes and interphase nuclei from a broad range of cells and tissues. In situ hybridization techniques use DNA probes which can hybridize to entire chromosomes or to single unique sequence genes and serve as a powerful adjunct to classical cytogenetic tests . The applications of FISH include aneuploidy detection, translocation and struc tural breakpoint analysis, microdeletion detection, and gene mapping, to be elaborated further in another chapter in this book. In this chapter we focus on the principles and methodology of FISH.
