UNIT 18.4 Quantitative Fluorescence In Situ Hybridization (Q-FISH)

  1. Steven S.S. Poon,
  2. Peter M. Lansdorp

Published Online: 1 NOV 2001

DOI: 10.1002/0471143030.cb1804s12

Current Protocols in Cell Biology

Current Protocols in Cell Biology

How to Cite

Poon, S. S. and Lansdorp, P. M. 2001. Quantitative Fluorescence In Situ Hybridization (Q-FISH). Current Protocols in Cell Biology. 12:18.4:18.4.1–18.4.21.

Author Information

  1. BC Cancer Research Centre and University of British Columbia, Vancouver, Canada

Publication History

  1. Published Online: 1 NOV 2001
  2. Published Print: OCT 2001


This unit describes a quantitative technique for measuring the lengths of telomere repeat sequences in individual chromosomes from single metaphase cells. The technique is based on fluorescence in situ hybridization (FISH) adapted for use with peptide nucleic acid (PNA) probes. PNA is an example of novel synthetic oligonucleotide “mimetic” which has a higher affinity than regular oligonucleotide (RNA or DNA) probes for complementary single-strand (ss) DNA sequences. PNA oligonucleotides have excellent penetration properties due to their small size (typically 15 to 18-mers) and can be directly labeled with fluorochromes. These properties have been exploited to develop quantitative fluorescence in situ hybridization (Q-FISH) onto denatured single-stranded chromosomal DNA target sequences. The latter can be present in preparations of fixed metaphase cells on slides (Q-FISH) or in heat-treated (interphase) cells in suspension (flow-FISH).