Transmission of X-ray-induced reciprocal translocations in normal male mice and in male mice with a reduced sperm count due to translocation homozygosity.
Normal (+/+) and translocation T(1; 11.13S)70H homozygous (T/T) male mice received 2 X 2.5 Gy X-rays with a 24-h interval. After 120 days, the frequency of late diplotene-metaphase I spermatocytes with translocation multivalents was 14.1% for +/+ and 13.7% for T/T males, respectively, in one group of animals of each type. The difference is not significant. A second group was allowed to sire progeny for 60 days with 2 normal females per week. Reciprocal translocations detectable at diakinesis/metaphase I were observed in 2.5% of the 395 male progeny from the irradiated +/+ fathers, and in 2.9% of the 489 male progeny from the irradiated T/T fathers. This leads to a pooled estimated transmission of 0.81 +/- 0.19. Translocations induced in the long 11.13 metacentric chromosome were not transmitted with a different frequency. The rate of heritable induced translocations in this study was 5.4 X 10(-5)/rad/gamete. On the basis of the data of Generoso et al. (1984) for the frequency of the heritable spontaneous translocations in male mice, it is concluded that, because of their low doubling dose (3.3-4.6 rad), the spontaneous translocations are probably of postmeiotic origin.
D000818:Animals; D005260:Female; D005298:Fertility / Q000528:radiation effects; D005313:Fetal Death / Q000209:etiology; D006720:Homozygote; D008297:Male; D051379:Mice; D008817:Mice, Mutant Strains; D009845:Oligospermia / Q000235:genetics*; D011247:Pregnancy; D013090:Spermatocytes / Q000528:radiation effects / Q000648:ultrastructure; D014178:Translocation, Genetic / Q000528:radiation effects