title: Lack of effect on the chromosomal non-disjunction in aged female mice after low dose X-irradiation.
abstract: Karyotypes were determined in 1064 embryos of aged C57/BL mothers. The virgin female mice were irradiated with 0, 4, 8 or 16 R of X-rays, respectively, and placed with young untreated males 5 days after irradiation. 10.5-days old embryos were recovered from the uterus. Aneuploid embryos classified as alive (heart beats observed at the dissection) were 1 monosomic in the control group (496 embryos) and 2 trisomics in the irradiated group (568 embryos). The number of aneuploid embryos classified as dead was 4 trisomic cases in the control group and 3 trisomics in the irradiated group. The data indicate that trisomic embryos are not uncommon in the mouse but are eliminated in post-implantation death. In contrast to the results of Yamamoto et al. the present data do not demonstrate an increased frequency of chromosome abnormalities in embryos of aged mice X-irradiated before mating as compared to non-irradiated ones.
mesh_terms: D000375:Aging; D000818:Animals; D002869:Chromosome Aberrations; D002875:Chromosomes / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D004622:Embryo, Mammalian; D005260:Female; D005821:Genetic Techniques; D008098:Litter Size; D051379:Mice; D008810:Mice, Inbred C57BL; D011247:Pregnancy; D012737:Sex Factors; D014965:X-Rays