Medical Definition of Hybridization, fluorescent in situ

  • Medical Author:
    Melissa Conrad Stöppler, MD

    Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

Hybridization, fluorescent in situ: An important molecular cytogenetic method for identifying chromosomes and parts of chromosomes, deciphering chromosome rearrangements, and locating genes on chromosomes.

"Fluorescent" means emitting light that comes from a reaction within the emitter. "In situ" refers to the fact that this techniques is done with the chromosomes, cells or tissue in place (in situ) on a microscope slide.

In situ hybridization is a technique in which single-stranded nucleic acids (DNA or RNA) are permitted to interact so that complexes, or hybrids, are formed by molecules with sufficiently similar, complementary sequences. Through nucleic acid hybridization, the degree of sequence identity can be determined and specific sequences detected and sometimes those sequences can be located on a specific chromosome. A nucleic acid labelled with a fluorescent dye is hybridized to suitably prepared cells or histological sections. This is used particularly to look for specific transcription or localization of genes to specific chromosomes.

Fluorescent in situ hybridization is abbreviated FISH.

Reviewed on 9/7/2018

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