Image Processing, Computer-AssistedOrganizers, EmbryonicNucleolus Organizer RegionGoosecoid ProteinBody PatterningEmbryonic InductionGastrulaXenopus ProteinsSilver StainingEmbryologyGene Expression Regulation, DevelopmentalOtx Transcription FactorsEmbryo, NonmammalianZebrafish ProteinsHomeodomain ProteinsXenopusMesodermFibroblast Growth Factor 8Nodal ProteinRhombencephalonNotochordHydraMesencephalonAxisNodal Signaling LigandsZebrafishIntercellular Signaling Peptides and ProteinsWnt ProteinsHeadIn Situ HybridizationEctodermXenopus laevisBone Morphogenetic ProteinsTissue TransplantationNervous SystemLIM-Homeodomain ProteinsMorphogenesisSilverCell NucleolusGenes, HomeoboxWnt1 ProteinActivinsLeft-Right Determination FactorsTranscription FactorsEndodermSignal TransductionMetencephalonBlastulaFetal ProteinsT-Box Domain ProteinsGlycoproteinsProteinsTwins, ConjoinedFibroblast Growth FactorsBlastodermMatrix Attachment Region Binding ProteinsBone Morphogenetic Protein 4Chick EmbryoMolecular Sequence DataSilver Nitratebeta CateninHepatocyte Nuclear Factor 3-betaAmphibiansTransforming Growth Factor betaRepressor ProteinsInhibinsTectum MesencephaliAmino Acid SequenceNeural PlateTrans-ActivatorsDrug PackagingHedgehog ProteinsProsencephalonChromosomesMicroinjectionsStaining and LabelingBlastomeresNerve Tissue ProteinsCentral Nervous SystemVertebratesChordataFollistatinDNA-Binding ProteinsTailDNA, RibosomalGenes, DevelopmentalChordata, NonvertebrateCytoskeletal ProteinsHMGB ProteinsEmbryonic DevelopmentRNA, MessengerRNA, RibosomalBlastocystWingCarrier ProteinsBone Morphogenetic Protein ReceptorsBase SequenceCell LineageQuailCell Differentiation