🦠microbiology review

Fluorescence in situ hybridization (FISH)

Written by the Fiveable Content Team • Last updated August 2025
Written by the Fiveable Content Team • Last updated August 2025

Definition

Fluorescence in situ hybridization (FISH) is a molecular technique used to detect and localize specific DNA or RNA sequences in cells or tissue samples. It employs fluorescent probes that bind to complementary nucleic acid sequences, allowing visualization under a fluorescence microscope.

AP course connection

Topic 2.3: 2.3 Instruments of Microscopy

Unit 2

5 Must Know Facts For Your Next Test

  1. FISH is commonly used for identifying the presence and location of specific genes or chromosomal abnormalities.
  2. The technique involves hybridizing a fluorescently labeled probe with the target nucleic acid sequence in fixed cells or tissues.
  3. FISH can be applied to both metaphase chromosomes and interphase nuclei, making it versatile in genetic diagnostics.
  4. The specificity of FISH depends on the design of the fluorescent probe, which must be complementary to the target sequence.
  5. FISH is widely used in clinical settings for diagnosing genetic disorders, cancer, and infectious diseases.
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