What is fluorescence in situ hybridization (FISH)?

Fluorescence in situ hybridization (FISH) is a molecular cytogenetic technique that detects and localizes specific nucleic acid sequences (DNA and RNA) based on the complementary nature of DNA or DNA/RNA. Fluorescent probes are specially designed to hybridize with the target DNA or RNA in situ. Once hybridization is completed and unhybridized probes are removed, the target nucleic acids can be located and visualized by fluorescence microscopy. This technique is often used for finding specific features in DNA, serving as an important tool for understanding a variety of chromosomal abnormalities and other genetic mutations.