I. Genetic and environmental effects on preimplantation development of mouse embryo in vitro

To examine the degree of the relative contribution of genetic and environmental effects to preimplantation development of mouse embryo in vitro, two-cell stage embryos collected from oviducts of five strains of inbred mice (DDD/Qdj, C3H/Qdj, C57BL/6J Sea, DBA/1J Sea, and BALB/C Sea) were cultivated up to the stage of expanded blasytocyst for 72 hr. Both fertility and survival rates were calculated in each recipient and also in each strain. A Student-Newman-Keuls test for both rates showed a significant inter-strain difference and an analysis of variance done to estimate the relative importance of genetic and environmental effects on the preimplantation development of embryo showed a low degree of genetic determination for both rates. It was thus possible to conclude that the environmental effect played a more important role on preimplantation development of mouse embryo in vitro.