Fluorescence In Situ Hybridization (FISH) to Metaphase and Interphase Chromosomes

The unambiguous identification of human chromosomes became possible with the discovery and implementation of G-banding techniques (1). Almost immediately, investigators developed various methods to physically map specific DNA sequences to banded chromosomes. A commonly used early technique involved the hybridization in situ of radioactively labeled probes to heat-denatured human metaphase chromosomes (reviewed in 2). These techniques were efficient, yet costly, time-consuming, and technically difficult. Isotopic hybridization in situ was rapidly superseded by nonisotopic techniques-especially those utilizing fluorescently labeled probes (3-6). This chapter describes basic methodology for the accomplishment of metaphase and interphase fluorescence in situ hybridization (FISH).