X-ray-induced breakage and rejoining of human interphase chromosomes

Michael N. Cornforth, Joel S. Bedford

Research output: Contribution to journalArticlepeer-review

160 Scopus citations


A method was developed for the high-resolution measurement of breaks in prematurely condensed chromosomes at the G1 phase of the cell cycle. The dose response for fragments (breaks) produced immediately after x-irradiation of confluent cultures of normal human cells was linear down to 10.9 rad (0.109 Gy) and extrapolated to zero effect at zero dose. The curve had a slope of 0.063 breaks per cell per rad, which is at least an order of magnitude greater than that for breaks scored in the same cells after they have progressed to mitosis following subculture. When incubated at 37°C half of the breaks disappeared in 2 hours. A slower, perhaps nonrejoining component was apparent at later incubation times. The initial rate of break rejoining was similar to the rate of increase in survival after incubation because of the repair of potentially lethal damage and is also in close agreement with recently reported values for the rejoining of double-strand breakage in DNA.

Original languageEnglish (US)
Pages (from-to)1141-1143
Number of pages3
Issue number4628
StatePublished - 1983
Externally publishedYes

ASJC Scopus subject areas

  • General


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