Montero Herradón, SaraGarcía-Ceca Hernández, José JavierZapata González, Agustín GregorioPassos, G.A.Mendes-da-Cruz, D.A.Savino, W.2025-06-172025-06-172025Montero-Herradón, S., García-Ceca, J., Zapata, A.G. (2025). Thymus Ontogeny and Development. In: Passos, G.A., Mendes-da-Cruz, D.A., Savino, W. (eds) Thymus Transcriptome and Cell Biology. Advances in Experimental Medicine and Biology, vol 1471. Springer, Cham. https://doi.org/10.1007/978-3-031-77921-3_2978303177920697830317792130065-259810.1007/978-3-031-77921-3_2https://hdl.handle.net/20.500.14352/121459This review has been funded by the Spanish Ministry of Science, Innovation and Universities (RTI2018-093938-B-I00) and ‘Instituto de Salud Carlos III (ISCIII)’ through the project RD21/0017/0010, Red Española de Terapias Avanzadas (TERAV, ISCIII), co-funded by the ‘European Union Program NextGenerationEU’ and the ‘Recovery, Transformation and Resilience Plan’.The thymus is a primary lymphoid organ composed of a three-dimensional (3D) epithelial network that provides a specialized microenvironment for the phenotypical and functional maturation of lymphoid progenitors. The specification of the pharyngeal endoderm to thymus fate occurs during the early stages of thymic organogenesis, independent of the expression of the transcription factor Foxn1. However, Foxn1 governs the later organogenesis of thymus together with the colonizing lymphoid cells. In the present chapter, we will review recent evidence on the topic covered in our original chapter (Muñoz and Zapata 2019). It described the early development of thymus and its resemblance to the development of endoderm-derived epithelial organs based on tubulogenesis and branching morphogenesis as well as the molecules known to be involved in these processes.engbook part2214-8019https://doi.org/10.1007/978-3-031-77921-3_2metadata only access57ThymusOntogenyFoxn1OrganogenesisLymphoid progenitorsPharyngeal endodermTubulogenesisBranching morphogenesisBiología celular (Biología)Genética2407 Biología Celular2409 Genética