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Molecular Toxicology Protocols pp 85–95Cite as

The Comet Assay

A Sensitive Genotoxicity Test for the Detection of DNA Damage

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Part of the book series: Methods in Molecular Biology™ ((MIMB,volume 291))

Abstract

The comet assay or single-cell gel (SCG) test is a microgel electrophoresis technique that measures DNA damage at the level of single cells. A small number of cells suspended in a thin agarose gel on a microscope slide is lysed, electrophoresed, and stained with a fluorescent DNA binding dye. Cells with increased DNA damage display increased migration of chromosomal DNA from the nucleus toward the anode, which resembles the shape of a comet. In its alkaline version, which is mainly used, DNA single-strand breaks, DNA double-strand breaks, alkali-labile sites, and single-strand breaks associated with incomplete excision repair sites cause increased DNA migration. On the other hand, crosslinks (DNA-DNA or DNA-protein) can lead to decreased DNA migration. Variations of the comet assay have been established for the detection of specific DNA base modifications. Here we describe the basic methodology of the alkaline comet assay, establishing a sensitive protocol for obtaining reproducible and reliable data. Applications of the comet assay for detecting DNA damage in individual cells are briefly reviewed.

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Author information

Authors and Affiliations

  1. Abteilung Humangenetik, Universitätsklinkum Ulm, Ulm, Germany

    Günter Speit

  2. Novartis Pharma AG, Basel, Switzerland

    Andreas Hartmann

Authors
  1. Günter Speit
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  2. Andreas Hartmann
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Editor information

Editors and Affiliations

  1. Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA

    Phouthone Keohavong  & Stephen G. Grant  & 

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© 2005 Humana Press Inc.

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Speit, G., Hartmann, A. (2005). The Comet Assay. In: Keohavong, P., Grant, S.G. (eds) Molecular Toxicology Protocols. Methods in Molecular Biology™, vol 291. Humana Press. https://doi.org/10.1385/1-59259-840-4:085

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  • DOI: https://doi.org/10.1385/1-59259-840-4:085

  • Publisher Name: Humana Press

  • Print ISBN: 978-1-58829-084-7

  • Online ISBN: 978-1-59259-840-3

  • eBook Packages: Springer Protocols

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