Organizers, EmbryonicNucleolus Organizer RegionFetal DevelopmentEmbryonic and Fetal DevelopmentEmbryonic DevelopmentGoosecoid ProteinGene Expression Regulation, DevelopmentalBody PatterningGastrulaEmbryonic InductionEmbryo, NonmammalianXenopus ProteinsPregnancyFetusSilver StainingIn Situ HybridizationZebrafish ProteinsEmbryologyMesodermHomeodomain ProteinsZebrafishEmbryo, MammalianOtx Transcription FactorsXenopusBlastocystMorphogenesisPlacentaGestational AgeFibroblast Growth Factor 8RhombencephalonTranscription FactorsNotochordMolecular Sequence DataWnt ProteinsNodal ProteinNervous SystemEctodermXenopus laevisBone Morphogenetic ProteinsRNA, MessengerSignal TransductionIntercellular Signaling Peptides and ProteinsMesencephalonCell DifferentiationHeadHydraNodal Signaling LigandsChick EmbryoAxisGenes, HomeoboxAmino Acid SequenceTissue TransplantationBase SequenceLIM-Homeodomain ProteinsEndodermFetal ViabilityBlastulaCell NucleolusProteinsWnt1 ProteinSilverPrenatal Exposure Delayed EffectsTeratogenesisFetal ProteinsPhenotypeActivinsDNA-Binding ProteinsMaternal-Fetal ExchangeImmunohistochemistryZygoteOocytesT-Box Domain ProteinsPlacentationMutationEmbryo ImplantationEmbryo Culture TechniquesMice, KnockoutMaternal Nutritional Physiological PhenomenaFibroblast Growth FactorsEmbryo LossBlastodermFetal DeathLeft-Right Determination FactorsPregnancy, AnimalCell LineageHedgehog ProteinsFetal ResorptionTime FactorsOrganogenesisFetal Growth RetardationMice, TransgenicModels, BiologicalRepressor ProteinsSequence Homology, Amino AcidCloning, Molecularbeta CateninAnimals, NewbornMice, Inbred C57BLReverse Transcriptase Polymerase Chain ReactionGlycoproteins