The effect of PMSG dose on the incidence of chromosomal anomalies in mouse embryos fertilized in vitro.

Chromosomal analysis of first-cleavage mouse embryos obtained by fertilization of TO eggs with TO spermatozoa in vitro revealed that the incidence of polyploidy was proportional to the dose of PMSG given to the donor females. The dose-response was shown to be linear, with the level of polyploidy rising from 8-0% with a PMSG dose of 1-5 i.u./female to 20-8% with 10-0 i.u./female. A total of 64 polyploid embryos was found among the 452 examined and in all cases the polyploidy was the result of polyspermy or fertilization by diploid spermatozoa.