ExtremitiesLimb BudsLimb Deformities, CongenitalChick EmbryoMesodermGene Expression Regulation, DevelopmentalCartilageChondrogenesisPolydactylyFibroblast Growth Factor 4Embryo, MammalianEctodermHedgehog ProteinsMorphogenesisFibroblast Growth Factor 8ForelimbFibroblast Growth FactorsBody PatterningIn Situ HybridizationWingLimb SalvageEmbryonic InductionHomeodomain ProteinsHindlimbBone Morphogenetic ProteinsMSX1 Transcription FactorGenes, HomeoboxQuailPhantom LimbAmbystoma mexicanumTrans-ActivatorsBone Morphogenetic Protein 2Fibroblast Growth Factor 10RegenerationTranscription FactorsEctromeliaSomitesEmbryonic and Fetal DevelopmentProteinsToesAvian ProteinsTretinoinMolecular Sequence DataBone Morphogenetic Protein 4SyndactylyLegSalamandridaeTeratogensLower ExtremitySignal TransductionKruppel-Like Transcription FactorsCell DifferentiationPaired Box Transcription FactorsCoturnixFeathersSOX9 Transcription FactorIschemia