title: Genetic basis for the evolution of organ morphogenesis: the case of spalt and cut in the development of insect trachea.
abstract: It is not clear how simple genetic changes can account for the coordinated variations that give rise to modified functional organs. Here, we addressed this issue by analysing the expression and function of regulatory genes in the developing tracheal systems of two insect species. The larval tracheal system of Drosophila can be distinguished from the less derived tracheal system of the beetle Tribolium by two main features. First, Tribolium has lateral spiracles connecting the trachea to the exterior in each segment, while Drosophila has only one pair of posterior spiracles. Second, Drosophila, but not Tribolium, has two prominent longitudinal branches that distribute air from the posterior spiracles. Both innovations, while considered different structures, are functionally dependent on each other and linked to habitat occupancy. We show that changes in the domains of spalt and cut expression in the embryo are associated with the acquisition of each structure. Moreover, we show that these two genetic modifications are connected both functionally and genetically, thus providing an evolutionary scenario by which a genetic event contributes to the joint evolution of functionally inter-related structures.
authors: Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), Functional Genomics and Evolution, Department Passeig Marítim de la Barceloneta 37-49, Barcelona 08003, Spain Institut de Biología Molecular de Barcelona (CSIC), Carrer de Baldiri Reixac 10, Barcelona, Catalonia 08028, Spain.
authors: Cristina
authors: C
authors: de Miguel
authors: Institut de Biología Molecular de Barcelona (CSIC), Carrer de Baldiri Reixac 10, Barcelona, Catalonia 08028, Spain Institut de Recerca Biomèdica de Barcelona, Carrer de Baldiri Reixac 10, Barcelona, Catalonia 08028, Spain.
authors: Friedemann
authors: F
authors: Linsler
authors: Institut de Biología Molecular de Barcelona (CSIC), Carrer de Baldiri Reixac 10, Barcelona, Catalonia 08028, Spain Institut de Recerca Biomèdica de Barcelona, Carrer de Baldiri Reixac 10, Barcelona, Catalonia 08028, Spain jcrbmc@ibmb.csic.es xavier.franch@ibe.upf-csic.es.
authors: Jordi
authors: J
authors: Casanova
authors: Institute of Evolutionary Biology (CSIC-Universitat Pompeu Fabra), Functional Genomics and Evolution, Department Passeig Marítim de la Barceloneta 37-49, Barcelona 08003, Spain jcrbmc@ibmb.csic.es xavier.franch@ibe.upf-csic.es.
authors: Xavier
authors: 0000-0002-7465-6729
authors: X
authors: Franch-Marro
mesh_terms: D000818:Animals; D004330:Drosophila / Q000378:metabolism; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism; D009024:Morphogenesis / Q000235:genetics / Q000502:physiology*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology; D014132:Trachea / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014231:Tribolium / Q000378:metabolism*
chemical_list: D029721:Drosophila Proteins; D018398:Homeodomain Proteins; D019476:Insect Proteins; D009687:Nuclear Proteins; D014157:Transcription Factors; C066381:ct protein, Drosophila; C085793:salm protein, Drosophila
keywords: Cut; Drosophila; Evolution; Morphogenesis; Spalt; Spiracles; Trachea; Tribolium