Cell LineageCell DifferentiationMicroscopyMicroscopy, ElectronStem CellsPhylogenyGene Expression Regulation, DevelopmentalMicroscopy, Electron, ScanningMice, TransgenicMolecular Sequence DataTranscription FactorsHematopoietic Stem CellsMicroscopy, FluorescenceCells, CulturedMicroscopy, ConfocalEvolution, MolecularMice, Inbred C57BLHomeodomain ProteinsBase SequenceThymus GlandEmbryonic Stem CellsMicroscopy, Atomic ForceMesodermGerm CellsEmbryo, MammalianPhenotypeSignal TransductionMorphogenesisBiological EvolutionBasic Helix-Loop-Helix Transcription FactorsFlow CytometryEmbryo, NonmammalianStaining and LabelingCell DivisionGreen Fluorescent ProteinsMice, KnockoutModels, BiologicalHematopoiesisBone Marrow CellsSequence Analysis, DNAImmunohistochemistryCell LineChimeraMultipotent Stem CellsEndodermDNA-Binding ProteinsEctodermIn Situ HybridizationB-LymphocytesGene Expression RegulationLymphopoiesisHistocytochemistryTime FactorsMicroscopy, Scanning TunnelingReceptors, NotchUrochordataClone CellsCell SeparationEmbryonic DevelopmentMutationCell ProliferationRNA, MessengerHistologyBlastomeresGene ExpressionT-LymphocytesSpecies SpecificityMicroscopy, Phase-ContrastFluorescent DyesAmino Acid SequenceGenetic VariationCaenorhabditis elegansBody PatterningEnteroendocrine CellsBlastocystPluripotent Stem CellsReverse Transcriptase Polymerase Chain ReactionNeural CrestImage Processing, Computer-AssistedLensesNeuronsIntegrasesTrophoblastsMicroscopy, PolarizationGerm LayersFluorescent Antibody TechniqueZebrafishEpithelial CellsDNA PrimersCell CountDrosophilaMicroscopy, Fluorescence, MultiphotonMicroscopy, Electron, TransmissionCell Culture TechniquesPolymerase Chain ReactionAnimals, Genetically ModifiedEquipment DesignLuminescent ProteinsAutoradiographyTranscription, Genetic