High Effectiveness of Chronic Neutron Exposures for the Induction of Specific Locus Mutations in Mice

MAMMALIAN radiation genetics has been largely concerned with the effects of X- and γ-irradiation, about which much has been learned in recent years. Surprisingly little work has been done with neutrons, although it is known that fast neutrons of modal energy around 1 MeV are about six times as effective as acute X-irradiation for the induction of dominant lethal mutations in mouse spermatozoa, whether the neutron dose is administered at high or at low intensity1,2. For the assessment of human hazards from high linear energy transfer radiation, it is particularly important to investigate the effectiveness of chronic neutron exposures with respect to the induction of point mutations in immature germ-cells of mammals. An experiment of this type, using the specific locus method, is now in progress and has revealed a surprisingly high yield of mutations following fast neutron irradiation of mouse spermatogonia.