Genetic Constitution of Early Stage Pig Embryos and Embryo Mortality

Cytogenetics of Porcine Sperm Chromosomes Following IVF of Zona-Free Hamster Oocytes

“…Smith and Marlow [25] reported one aneuploidic embryo out of 76 day-25 embryos, which was monosomic for chromosome 16. Other workers have observed no aneuploidy in pig blastocysts [lo, 161 or preimplantation morulae [9], although many workers reported quite high levels of polyploidy (1.2-8.0%) [28]. From our observations on pig sperm chromosomes we would have expected a higher incidence of aneuploidy in early pig embryos.…”

“…From our observations on pig sperm chromosomes we would have expected a higher incidence of aneuploidy in early pig embryos. Possibly such embryos are aborted before the stages at which previous workers have karyotyped preimplantation or postimplantation pig embryos [9,10,16,191. However, studies on genetically unbalanced embryos from reciprocal translocations [28] show that none of the genetically unbalanced embryos aborted before the ninth day of development, and many survived much longer, It would appear that aneuploidic embryos should have survived to be encompassed in these previous studies [9,10,16,191, unless aneuploidic embryos were more prone to preimplantation loss.…”