Radiation-induced germline instability at minisatellite loci

Purpose: To review the results of recent studies on radiation-induced germl ine instability at mammalian minisatellite loci. Results: Evidence has been obtained recently that germline mutation at mini satellites is remarkably sensitive to ionizing radiation, in both mice and humans. In mice, an elevated mutation rate was found after acute irradiatio n of pre-meiotic spermatogonia, with a doubling dose of 0.33 Gy, a value cl ose to those obtained in mice after acute spermatogonia irradiation using o ther systems for mutation detection. In humans, analysis of germline mutati on rate at minisatellites among children born in areas of the Mogilev distr ict of Belarus, which was heavily polluted after the Chernobyl accident, ha s shown a twofold higher mutation rate in exposed families compared with no nirradiated families from the United Kingdom. within the Belarus cohort, th e mutation rate was significantly greater in families exposed to a higher p arental radiation dose, consistent with radiation induction of germline mut ation. The data in this study also demonstrate the indirect nature of radia tion-induced germline mutation at mammalian minisatellite loci suggesting a strong similarity with the phenomenon of genomic instability in somatic ce lls. Conclusions: Minisatellite loci provide a powerful system for the efficient monitoring of germline mutation in humans and are capable of detecting ind uced mutations in relatively small population samples.