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Updated: Aug 25, 2026

Measuring DNA Damage and Repair in Mouse Splenocytes After Chronic In Vivo Exposure to Very Low Doses of Beta- and Gamma-Radiation
Published on: July 3, 2015
A threshold exists in the dose-response relationship for somatic mutation frequency induced by X irradiation of
Takao Koana1, Yoshio Takashima, Mikie O Okada
1Environmental Biotechnology Laboratory, Railway Technical Research Institute, Tokyo 185-8540, Japan. koana@criepi.denken.or.jp
Abstract:
The dose-response relationship of ionizing radiation and its stochastic effects has been thought to be linear without any thresholds. The basic data for this model were obtained from mutational assays in the male germ cells of the fruit fly Drosophila melanogaster. However, it is more appropriate to examine carcinogenic activity in somatic cells than in germ cells. Here the dose-response relationship of X irradiation and somatic mutation was examined in Drosophila. A threshold at approximately 1 Gy was observed in DNA repair-proficient flies. In the repair-deficient siblings, the threshold was smaller and the inclination of the dose-response curve was much steeper. These results suggest that the dose-response relationship between X irradiation and somatic mutation has a threshold and that the DNA repair function contributes to its formation.
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