DNA damage and repair in individual cells: applications of the comet assay in radiobiology.

The comet assay is a single-cell gel electrophoresis method that can measure a variety of types of DNA damage, and repair of damage, in individual cells. It is now in widespread use in genetic toxicology and oncology. This review describes the history of the development of this method and its applications in radiation biology, with particular emphasis on the use of the comet assay to measure heterogeneity in DNA damage in cells exposed to ionizing radiation.