Environmental and epigenetic effects upon preimplantation embryo metabolism and development

In vitro fertilization has provided a unique window into the metabolic processes that drive embryonic growth and development from a fertilized ovum to a competent blastocyst. Post-fertilization development is dependent upon a dramatic reshuffling of the parental genomes during meiosis, as well as epigenetic changes that provide a new and autonomous set of instructions to guide cellular differentiation both in the embryo and beyond. Although early literature focused simply on the substrates and culture conditions required for progress through embryonic development, more recent insights lead us to suggest that the surrounding environment can alter the epigenome, which can, in turn, impact upon embryonic metabolism and developmental competence. In vitro fertilization has provided a unique window into the metabolic processes that drive embryonic growth and development from a fertilized ovum to a competent blastocyst. Post-fertilization development is dependent upon a dramatic reshuffling of the parental genomes during meiosis, as well as epigenetic changes that provide a new and autonomous set of instructions to guide cellular differentiation both in the embryo and beyond. Although early literature focused simply on the substrates and culture conditions required for progress through embryonic development, more recent insights lead us to suggest that the surrounding environment can alter the epigenome, which can, in turn, impact upon embryonic metabolism and developmental competence. embryonic cells derived from the mitotic divisions of a fertilized ovum. the fluid filled cavity in the blastocyst stage embryo. a preimplantation embryo after five mitotic divisions that consists of the inner cell mass and a thin trophoblast layer enclosing the blastocoel, which forms as the morula passes from the oviduct to the uterus. formation of the blastocoel through the accumulation of fluid within the morula. a series of symmetrical mitotic cell divisions during which the size of the fertilized ovum remains unchanged as the blastomeres become progressively smaller with each division. process during which blastomeres change their shape and align themselves tightly against one another to form a morula in preparation for cavitation and blastocyst formation. activation of transcription from the embryonic genome that occurs at the two- to eight-cell stage, depending upon the species, and which takes control of development from maternal transcripts present in the oocyte. the fusion of two gametes to generate a zygote. reproductive cell (sperm or oocyte) that contributes a haploid set of chromosomes to the zygote at fertilization. the formation of an attachment between the blastocyst and uterus at the end of preimplantation development that leads to invasion of the uterine endometrial tissues by trophoblast cells in humans and some other mammals to begin the formation of a placenta. a cluster of cells derived from blastomeres positioned inside the morula that become located eccentrically within the blastocyst. They are the source of embryonic stem cells and eventually give rise to all embryonic germ layers. a preimplantation embryo after three mitotic divisions that compacts into a solid, spherical mass in which individual cells are no longer visible. a structure formed by trophoblast and mesodermal derivatives of the embryo that provides an interface for the fetus with the maternal circulatory system during gestation. one of two haploid nuclei in a zygote produced by meiosis and derived from either the oocyte or sperm. the combination of chromosomes from two pronuclei to form a diploid nucleus as the zygote undergoes its first mitotic division. the first epithelial cells to form during preimplantation development; these are derived from blastomeres located on the outside of the morula and eventually contribute to the placenta and fetal membranes. cell formed by the fusion of two gametes whose genetic material is contained within two separate pronuclei.