LymphopoiesisB-LymphocytesInterleukin-7Precursor Cells, B-LymphoidLeukopoiesisHematopoiesisHematopoietic Stem CellsLymphoid Progenitor CellsB-Cell-Specific Activator ProteinBone Marrow CellsThymus GlandCell LineageMyelopoiesisReceptors, Interleukin-7Cell DifferentiationB-Lymphocyte SubsetsBone MarrowGene Rearrangement, B-LymphocyteMice, KnockoutT-LymphocytesMice, Inbred C57BLStromal CellsFlow CytometryKalanchoeThymocytesSpleenImmunoglobulin Light Chains, SurrogateIkaros Transcription FactorLymphocytesPre-B Cell ReceptorsPrecursor Cells, T-LymphoidReceptors, Antigen, B-CellMice, TransgenicAntigens, CD19LymphopeniaCells, CulturedFetusImmunoglobulin mu-ChainsTranscription Factor 7-Like 1 ProteinImmunoglobulin DMice, Inbred BALB CMice, Mutant StrainsHematopoiesis, ExtramedullaryImmunophenotypingChemokine CXCL12gamma CateninBone Marrow TransplantationDNA NucleotidylexotransferaseAgingStem CellsLymphocyte CountOsteopetrosisCell DivisionAntigens, CDImmunoglobulin lambda-ChainsChemokines, CXCTCF Transcription FactorsMyeloid CellsSulfur IsotopesSignal TransductionRadiation ChimeraMice, SCIDGene Rearrangement, T-LymphocyteNeprilysinLymphoid TissueImmunoglobulin MCoculture TechniquesYolk SacReceptors, NotchDNA-Binding ProteinsMembrane ProteinsLymphocyte SubsetsChimeraReceptor, Notch1