BlastomeresCytochalasinsCytochalasin DMicroscopy, Electron, ScanningEmbryo, MammalianEmbryo, NonmammalianCleavage Stage, OvumBlastocystEmbryonic DevelopmentChick EmbryoUrochordataEmbryo ImplantationPreimplantation DiagnosisFertilization in VitroMorulaEmbryonic and Fetal DevelopmentZygoteGene Expression Regulation, DevelopmentalPregnancyGastrulaEmbryonic InductionCryopreservationOocytesBody PatterningEmbryo TransferEctogenesisEmbryo LossNuclear Transfer TechniquesMesodermCloning, OrganismEctodermSea UrchinsMorphogenesisXenopus ProteinsZebrafishParthenogenesisIn Situ HybridizationZona PellucidaSperm Injections, IntracytoplasmicXenopus laevisCulture TechniquesEndodermSingle Embryo TransferXenopus