GENE REGULATORY NETWORK IN THE CONTEXT OF GENOME INSTABILITY IN HUMAN EMBRYO DEVELOPMENT

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Genomic instability is common in preimplantation embryos of a variety of species. Up to 80% of human cleavage stage embryos following in vitro fertilization acquire genetic mosaicism, but some may develop to normal individuals after uterine transfer. The causative mechanisms of this chromosome instability as well as the impact of acquired genetic anomalies on embryo development are not understood and remain speculative. Using novel methodologies for single-cell genome-plus-transcriptome sequencing (G&T-seq) of all cells of human preimplantation embryos from the fertilized egg to the blastocyst stage, we disclose insight in the gene regulatory network of preimplantation embryo development and how this is impacted by aneuploidy. Single-cell DNA CNV analysis revealed frequent missegregations of whole chromosomes as well as segmental rearrangements in all embryonic cell stages. Using these single-cell genomic profiles in combination with cell cleavage imaging of the developing embryos, we could deduce the origin of the abnormalities and construct cell lineages. Single-cell gene expression analysis of the same cells, classified the cells according to the embryonic developmental stage, the expression activation of the embryonic genome and disclosed the functional impact of acquired numerical and structural chromosome aberrations on development of the human embryo. Furthermore, the data reveals which genetic anomalies contribute to the epiblast cells in the blastocyst that provide the ectodermal, mesodermal and endodermal cell lineages, the building blocks of our organs. Genomic instability is common in preimplantation embryos of a variety of species. Up to 80% of human cleavage stage embryos following in vitro fertilization acquire genetic mosaicism, but some may develop to normal individuals after uterine transfer. The causative mechanisms of this chromosome instability as well as the impact of acquired genetic anomalies on embryo development are not understood and remain speculative. Using novel methodologies for single-cell genome-plus-transcriptome sequencing (G&T-seq) of all cells of human preimplantation embryos from the fertilized egg to the blastocyst stage, we disclose insight in the gene regulatory network of preimplantation embryo development and how this is impacted by aneuploidy. Single-cell DNA CNV analysis revealed frequent missegregations of whole chromosomes as well as segmental rearrangements in all embryonic cell stages. Using these single-cell genomic profiles in combination with cell cleavage imaging of the developing embryos, we could deduce the origin of the abnormalities and construct cell lineages. Single-cell gene expression analysis of the same cells, classified the cells according to the embryonic developmental stage, the expression activation of the embryonic genome and disclosed the functional impact of acquired numerical and structural chromosome aberrations on development of the human embryo. Furthermore, the data reveals which genetic anomalies contribute to the epiblast cells in the blastocyst that provide the ectodermal, mesodermal and endodermal cell lineages, the building blocks of our organs.