Lawrence Berkeley National Laboratory

The final weeks of male germ cell differentiation occur in a DNA repair-deficient environment and normal development depends on the ability of the egg to repair DNA damage in the fertilizing sperm. Genetic disruption of maternal DNA double-strand break repair pathways in mice significantly increased the frequency of zygotes with chromosomal structural aberrations after paternal exposure to ionizing radiation. These findings demonstrate that radiation-induced DNA sperm lesions are repaired after fertilization by maternal factors and suggest that genetic variation in maternal DNA repair can modulate the risk of early pregnancy losses and of children with chromosomal aberrations of paternal origin.