The cleavage rate of digynic triploid mouse embryos during the preimplantation period

Abstract

Triploidy is a lethal condition in mammals, with most dying at some stage between implantation and term. In humans, however, a very small proportion of triploids are liveborn but display a wide range of congenital abnormalities. In particular, the placentas of human diandric triploid embryos consistently display "partial" hydatidiform molar degeneration, while those of digynic triploids generally do not show these histopathological features. In mice, the postimplantation development of diandric and digynic triploid embryos also differs. While both classes are capable of developing to the forelimb bud stage, no specific degenerative features of their placentas have been reported. Diandric triploid mouse embryos are morphologically normal while digynic triploid mouse embryos consistently display neural tube and occasionally cardiac abnormalities. Previously it was shown that the preimplantation development of micromanipulated diandric triploid mouse embryos was similar to developmentally matched diploid control embryos. In this study, the preimplantation development of micromanipulated digynic triploid mouse embryos is analysed and compared with that of diandric triploid mouse embryos in order to determine whether there is any difference in cleavage rate between these two classes of triploids. Standard micromanipulatory procedures were used to insert a female or a male pronucleus into a recipient diploid 1-cell stage embryo. The karyoplast was fused to the cytoplasm of the embryo by electrofusion. These tripronucleate 1-cell stage embryos were then transferred to pseudopregnant recipients and, at specific times after the HCG injection to induce ovulation, the embryos were recovered and total cell counts made. These results were plotted and regression lines drawn.(ABSTRACT TRUNCATED AT 250 WORDS)

Chromosomal abnormalities in bovine embryos and their influence on development

“…Similarly, triploids and tetraploids among in vivo-derived bovine embryos possessed lower cell numbers relative to their diploid counterparts [31]. Studies on murine embryos lead to conflicting results: in one study, triploid embryos cleaved more slowly than diploid [32][33][34], whereas other reports indicate no difference in cleavage rates between these groups [35][36][37]. The difference in the results may be due to the different techniques used to induce polyploidy in these studies.…”

Effect of volume of oocyte cytoplasm on embryo development after parthenogenetic activation, intracytoplasmic sperm injection, or somatic cell nuclear transfer

“…In fact, 31% of somatic cloned embryos derived from AG oocytes failed first cell division, whereas in control oocytes, none of cloned embryo failed at this stage. It is known that abnormal karyotypes, such as triploidy (Sherard et al ., 1986; Henery & Kaufman, 1993), tetraploidy (Snow, 1975), or damaged chromosomes (Kusakabe et al ., 2001), do not prevent preimplantation development, but most of these embryos die during foetal development. Therefore, even if giant cloned embryos could develop to morulae or blastocysts, they might have no hope of developing to full term.…”

Unravelling the mystery of female meiotic drive: where we are

“…Furthermore, this direction of preferential segregation also allows a return to the euploid state in triploid worms [86]. Comparatively, triploid mice are inviable, and female mice can be XO or XXX, though only XO females are fertile [87,88]. The observed direction of preferential segregation of univalents in mice could suggest a bigger benefit to resolving XO aneuploidy rather than XXX aneuploidy, possibly due to other associated fitness costs of XXX individuals.…”