GastrulaMesodermCell DifferentiationEmbryo, NonmammalianGene Expression Regulation, DevelopmentalXenopus ProteinsBlastulaEmbryonic InductionEctodermIn Situ HybridizationMorphogenesisXenopus laevisBody PatterningGoosecoid ProteinGastrulationSea UrchinsOrganizers, EmbryonicPleurodelesBone Morphogenetic ProteinsXenopusHomeodomain ProteinsEndodermNervous SystemTranscription FactorsZebrafishSignal TransductionZebrafish ProteinsMolecular Sequence DataUrochordataBone Morphogenetic Protein 4Fetal ProteinsFibroblast Growth FactorsChick EmbryoRNA, MessengerT-Box Domain ProteinsCell LineageBase SequenceBlastomeresNeural CrestGenes, HomeoboxDNA-Binding ProteinsKillifishesAmino Acid SequenceCells, CulturedActivinsTrans-ActivatorsStem CellsMicroinjectionsBlastocystOtx Transcription FactorsOdontogenesisChordataEmbryonic DevelopmentWnt ProteinsNodal ProteinCloning, MolecularNotochordUreterProteinsGene ExpressionSequence Homology, Amino AcidSomitesLimb BudsEpitheliumToothPhenotypeTailRepressor ProteinsTretinoinDNA, ComplementaryCell DivisionEmbryo, MammalianTime FactorsIntercellular Signaling Peptides and ProteinsReverse Transcriptase Polymerase Chain ReactionTranscription, GeneticRhombencephalonExtremitiesMSX1 Transcription FactorImmunohistochemistryHedgehog ProteinsTransforming Growth Factor betaZygoteDNA PrimersModels, BiologicalEmbryonic and Fetal DevelopmentCell LineCell ProliferationNerve Tissue ProteinsSex DifferentiationCentral Nervous SystemGene Expression RegulationEmbryonic Stem CellsOrgan Culture TechniquesCell MovementMice, TransgenicCiona intestinalisFibroblast Growth Factor 9InhibinsMice, Knockout