[Preimplantation embryonic mortality--method of studying interstrain differences in the reparative activity of mouse ova].

Cytological analysis of preimplantation embryonic death in 101/HY, C57BL/6JY and CBA/lacY females crossed with hybird males F1 (BALB/cYxDBA/2Y) was carried out. Embryonic death was induced by thiophosphamide at a dose of 2 mg/kg, i. p. The maximum preimplantation death was recorded in 101/HY females (38.8%), the minimum in CBA/LacY females (21.9%). In C57BL/6JY females, the maximum preimplantation death accounted for 31.3%. Thus the same chromosome damage induced by thiophosphamide in late spermatids of F1CD2 males caused quantitative differences in embryonic mortality in females of different genotypes. The data obtained evidence that fertilized eggs are capable of repairing part of damage induced by paternal chromosomes. It was demonstrated that the preimplantation embryonic death can be used for studying strain differences from the reparative activity of mouse eggs.