[Cytological study of early embryonic mortality in laboratory mice]

Early embryogenesis of laboratory mice was studied cytologically. Preimplantation embryonic mortality in mice of the strains DBA/21Y, C57BL/61Y, 101/HY and in the CBWA females crossed with the B6 males did not exceed 4--6%. Mice of the strain AKRIY served as an exception with 29.6% preimplantation embryonic mortality level. Investigation of the chemically-induced dominant lethals showed that coarse structural chromosomal damages arrested the cleavage and caused the death of the embryos before the implantation.