Organizers, EmbryonicNucleolus Organizer RegionEmbryo, NonmammalianEmbryo, MammalianGoosecoid ProteinChick EmbryoBody PatterningGastrulaEmbryonic InductionGene Expression Regulation, DevelopmentalXenopus ProteinsEmbryo ImplantationBlastocystEmbryonic DevelopmentSilver StainingEmbryologyZebrafish ProteinsMesodermHomeodomain ProteinsZebrafishOtx Transcription FactorsXenopusIn Situ HybridizationEctodermBlastomeresMorphogenesisNotochordEmbryonic and Fetal DevelopmentNodal ProteinFibroblast Growth Factor 8RhombencephalonEmbryo LossXenopus laevisNervous SystemBone Morphogenetic ProteinsWnt ProteinsFertilization in VitroHeadCleavage Stage, OvumNodal Signaling LigandsEndodermTranscription FactorsMesencephalonIntercellular Signaling Peptides and ProteinsZygoteHydraAxisPregnancyTissue TransplantationGenes, HomeoboxMolecular Sequence DataBlastodermSignal TransductionLIM-Homeodomain ProteinsEmbryo DispositionCell NucleolusWnt1 ProteinCulture TechniquesMorulaSilverActivinsLeft-Right Determination FactorsT-Box Domain ProteinsOocytesMicroinjectionsAmino Acid SequenceProteinsCryopreservationRNA, MessengerFibroblast Growth FactorsBase SequenceDrosophilaDrosophila ProteinsCell DifferentiationAnimals, Genetically ModifiedGlycoproteinsBone Morphogenetic Protein 4MetencephalonDNA-Binding ProteinsRepressor ProteinsMutationSomitesEmbryo ResearchTrans-ActivatorsSingle Embryo TransferCloning, OrganismQuailCentral Nervous SystemBlastulaEctogenesisCell LineageHedgehog ProteinsFetal ProteinsTime Factorsbeta CateninTransforming Growth Factor betaNuclear Transfer TechniquesPhenotypeTwins, ConjoinedInhibins