Sensitivity of the mouse oocytes to the induction of translocations by ionizing radiations

Female mice from the C57B1 strain received 0, 50 or 200 R whole body X-irradiation and were mated to control males from the same strain. Using an air-drying technique, the testes of their F1males were analysed for the presence of chromosome rearrangements, but no translocation congurations were observed in the dividing spermatocytes of the 100 control males and of the 185 F1sons from irradiated females.Since meiotic preparations made one day after exposure of the females to X-irradiation showed the presence of chromosome rearrangements in some first meiotic metaphases, it could be inferred that the absence of translocated offspring after maternal X-ray exposure probably resulted from germinal selection.