Multicolor Fiber FISH

Various genetic abnormalities can be observed in many human diseases. They vary from numerical chromosomal aberrations, deletions, and amplification of specific regions to chromosomal translocations and insertions. In the past decade, numerous fluorescence in situ hybridization (FISH) methods have been developed for the detection of these abnormalities. FISH to interphase nuclei is one of the methods that is widely used to detect numerical chromosomal abnormalities, DNA amplification, and structural abnormalities ranging in size from approximately 10–1000 kilobases. Interphase cytogenetics requires a priori knowledge regarding the DNA sequences involved in the aberration. Particularly for the diagnostic detection of structural abnormalities such as chromosomal translocation breakpoints, the interphase method is highly dependent on the availability of appropriate breakpoint flanking probes.