[Preimplantation development of mouse embryos with monosomy of autosome No. 17]

Cytogenetic analysis was carried out for the ovulated oocytes and preimplantation embryos at the age of 3 and 4 days in the mice heterozygous by 2 Robertsonian translocations Rb (8; 17) 1 IEM and Rb (16; 17)7 Bnr. Out of 171 ovulated oocytes, 101 had chromosome aberrations, 44 nullisomy and 19 disomy by autosome 17. On the 3rd day of development the frequency of aneuploid embryos attained 41%; the same types of chromosome aberrations were found as in the oocytes and in about the same ratios: 15% of embryos had trisomy and 11.6% monosomy by autosome 17; the average number of blastomeres in these embryos did not differ from that in the diplod embryos; micronuclei were, as a rule, found in the cells of embryos with monosomy 17. Out of 100 karyotyped 4 days old embryos, 19 had trisomy by autosome 17, no monosomy by this chromosome was found; 20% of embryos contained 4 to 16 blastomeres with numerous micronuclei and picnoses. The trisomy by autosome 17 did not affect the preimplantation mouse development, whereas the embryos with monosomy died at the stage of 8 to 16 blastomeres.