Cleavage Stage, OvumBlastomeresBlastocystEmbryo, NonmammalianEmbryo TransferEmbryonic DevelopmentOocytesEmbryo, MammalianZygoteXenopus laevisEmbryo Culture TechniquesPregnancyFertilization in VitroFetal ViabilitySea UrchinsEmbryo ImplantationBlastulaEmbryonic and Fetal DevelopmentCryopreservationPregnancy RateVitrificationFertilizationGastrulaOvumPreimplantation DiagnosisSperm Injections, IntracytoplasmicXenopus ProteinsGene Expression Regulation, DevelopmentalMolecular Sequence DataPolar BodiesUrochordataOogenesisCell NucleusAmino Acid SequenceXenopusMorulaBody PatterningBase SequenceZebrafishGerm LayersRNA, Ribosomal, 18SIn Situ HybridizationCytoplasmTime FactorsEmbryonic InductionDNA CleavageMorphogenesisRNA, MessengerAneuploidyMeiosisCell DivisionCells, CulturedEctodermOctamer Transcription Factor-3RNA CleavagePregnancy, MultipleMutationCloning, MolecularMesodermZebrafish ProteinsSubstrate SpecificityHydrolysisEndopeptidasesTranscription Factors