Organizers, EmbryonicGastrulaGoosecoid ProteinNucleolus Organizer RegionBody PatterningEmbryonic InductionXenopus ProteinsEmbryo, NonmammalianGene Expression Regulation, DevelopmentalMesodermXenopusSilver StainingZebrafish ProteinsEctodermEmbryologyOtx Transcription FactorsHomeodomain ProteinsXenopus laevisZebrafishBlastulaIn Situ HybridizationNervous SystemNodal ProteinBone Morphogenetic ProteinsEndodermMorphogenesisRhombencephalonFibroblast Growth Factor 8Tissue TransplantationMesencephalonIntercellular Signaling Peptides and ProteinsHeadFetal ProteinsGenes, HomeoboxNotochordHydraLIM-Homeodomain ProteinsActivinsGastrulationT-Box Domain ProteinsAxisNodal Signaling LigandsWnt ProteinsTranscription FactorsSignal TransductionFibroblast Growth FactorsBlastodermMolecular Sequence DataSilverCell NucleolusBone Morphogenetic Protein 4ProteinsBlastomeresWnt1 ProteinGlycoproteinsPleurodelesAmino Acid SequenceLeft-Right Determination FactorsChick EmbryoChordataBlastocystInhibinsMicroinjectionsNeural PlateRepressor ProteinsAmphibiansMetencephalonTailCentral Nervous SystemChordata, NonvertebrateTransforming Growth Factor betaTrans-Activatorsbeta CateninSomitesSea Urchins