Radiation-Induced Mutation at Mammalian Minisatellite Loci

Abstract

Germline mutation at human minisatellite loci has been studied among children born in areas of the Mogilev district of Belarus heavily polluted after the Chernobyl accident. The overall mutation rate was twice as high in the exposed group as in control families An elevated rate was seen at all three independent sets of minisatellites (detected separately by multi-locus probes 33.15, 33.6 and six single-locus probes), indicating a generalised increase in minisatellite germline mutation rate in the Belarus families. Individual radiation doses for chronic external and internal exposure to 137Cs were estimated for each parent in the exposed group. Mutation rate was significantly higher in the more exposed Belarus families, providing direct evidence for radiation induction of germline mutation. Minisatellite mutations were also scored in the progeny of acute y-irradiated and non-irradiated CBA/H male mice. Mutation induction was only attributable to the spermatogonia stage of spermatogenesis and the frequency of mutations increased linearly with radiation dosage from 0.5 Gy to 1Gy. Our data suggest that minisatellite loci provide the efficient system for the monitoring of germline mutation in humans.