ABSTRACT
Fluorescence in situ hybridization (FISH) is a cell-based macromolecule recognition technique based on the complementary nature of DNA double strands. Fluorophore-coupled nucleotides can be enzymatically incorporated into cloned or amplified DNA fragments. The introduction of FISH into clinical cytogenetics excited the black-white banding pattern with fluorescent colors and evolved the field into molecular cytogenetics with expanded diagnostic applications. A wide variety of fluorophores are available, and several enzymatic reactions such as nick translation, random priming, and degenerative oligonucleotide primed polymerase chain reaction have been used to incorporate fluorophore-coupled nucleotides. Locus-specific, gene-targeted, regional or whole chromosome painting probes have been developed for diagnostic uses. Unique numerical chromosomal abnormalities such as small supernumerary marker chromosomes posed an interpretation challenge because the nature of these markers cannot be unambiguously identified by their morphology and banding pattern.
