Trisomy and triploidy induced by X-irradiation of mouse spermatocytes.
Analysis of second meiotic metaphase divisions in control and irradiated male mice shows that while the spontaneous rates of autosomal and sex chromosomal anaphase I non-disjunction are extremely low, they can be enhanced by X ray treatment of prophase spermatocytes. Irradiation at pre-leptotene results in a higher rate of anaphase I non-disjunction than does irradiation at pachytene. Early spermatogonia are relatively insensitive. Experiments to detect trisomic progeny among the F1 foetal offspring of male mice mated during weeks 5 and 6 following irradiation (sampling of irradiated early spermatocytes and late spermatogonia) showed that none were present. Possible explanations for this are considered. Two triploid foetuses were however found.
D000818:Animals; D005333:Fetus; D007621:Karyotyping; D008297:Male; D008540:Meiosis / Q000528:radiation effects*; D051379:Mice; D009940:Organoids; D011123:Polyploidy; D011831:Radiation Genetics; D013090:Spermatocytes / Q000528:radiation effects*; D013094:Spermatozoa / Q000528:radiation effects*; D013997:Time Factors; D014314:Trisomy; D014965:X-Rays