Project description:Chromosomal instability (CIN) occurs at high frequency during early in vitro embryogenesis and is known to be associated with early embryonic loss in humans. The chromosomal stability of in vivo-conceived cleavage stage embryos largely remains unknown. Here, we applied haplotyping and copy number profiling to investigate genomic architecture of 171 single bovine blastomeres and to compare the nature and frequency of CIN between in vivo embryos, in vitro embryos produced from ovum pick up with ovarian stimulation (OPU-IVF), and in vitro produced embryos from in vitro matured oocytes without ovarian stimulation (IVM-IVF). Our data shows that CIN is significantly lower in in vivo conceived cleavage stage embryos when compared to in vitro cultured embryos, as genomic stability of single blastomeres in both IVF embryos was severely compromised (P<0.0001)
Project description:The process of early development of mammals is subtly and accurately controlled by the regulation networks of embryo cells. Time course expression data measured at different stages during early embryo development process can give us valuable information by revealing the dynamic expression patterns of genes in genome wide scale. In this study, bovine embryo expression data were generated at oocyte, one cell stage, two cell stage, four cell stage, eight cell stage, sixteen cell stage, morula, and blastocyst; Human embryo expression data were generated at one cell stage, two cell stage, four cell stage, eight cell stage, morula, and blastocyst; Mouse embryo expression data were generated at one cell stage, two cell stage, four cell stage, eight cell stage, morula, and blastocyst. Experiment Overall Design: Bovine, Human, and Mouse embryos were harvested at successive stage from oocyte to blastocyste. Total RNAs were extracted, amplified and hybridized onto Affymetrix microarrays.
Project description:Aneuploidy represents the most prevalent form of genetic instability found in human embryos and is the leading genetic cause of miscarriage and developmental delay in newborns. Telomere DNA deficiency is associated with genomic instability in somatic cells and may play a role in development of aneuploidy commonly found in female germ cells and human embryos. To test this hypothesis, we developed a method capable of quantifying telomere DNA in parallel with 24-chromosome aneuploidy screening from the same oocyte or embryo biopsy. Aneuploid human polar bodies possessed significantly less telomere DNA than euploid polar bodies from sibling oocytes (-3.07 fold, P=0.016). This indicates that oocytes with telomere DNA deficiency are prone to aneuploidy development during meiosis. Aneuploid embryonic cells also possessed significantly less telomere DNA than euploid embryonic cells at the cleavage stage (-2.60 fold, P=0.002) but not at the blastocyst stage (-1.18 fold, P=0.340). The lack of a significant difference at the blastocyst stage was found to be due to telomere DNA normalization between the cleavage and blastocyst stage of embryogenesis and not due to developmental arrest of embryos with short telomeres. Heterogeneity in telomere length within oocytes may provide an opportunity to improve the treatment of infertility through telomere based selection of oocytes and embryos with reproductive competence.