title: Reticulate evolution in the Acrolophus subgroup (Centaurea L., Compositae) from the western Mediterranean: origin and diversification of section Willkommia Blanca.
abstract: Section Willkommia (Centaurea, Compositae) is endemic to the east-central portion of the Iberian Peninsula and northwestern Africa. The section has been included with sections Acrolophus and Phalolepis in the informal subgroup Acrolophus. We have used a molecular phylogenetic approach to test the hypothesis proposed by earlier authors that the diversification of section Willkommia involved a schizoendemic process from an ancestral syngameon. Comparative analysis of the transcribed spacer sequences of the nuclear ribosomal DNA (ITS and 3'ETS) regions reveals the presence of three different types of ribosomal sequences in the Acrolophus subgroup (referred to here as the Willkommia, Acrolophus-Phalolepis and Simulans ribotypes) which show a sectional-independent geographic structure. This evidence, together with the presence of additive polymorphic sites in the Willkommia sequences which agree with the geographic distribution of the taxa, suggests that members of section Willkommia and the western Mediterranean taxa of sections Acrolophus and Phalolepis fit a reticulate evolution model.
authors.affiliation: Departamento de Botánica, Universidad de Granada, Severo Ochoa, s/n, 18071 Granada, Spain. vsuarez@ugr.es
authors.forename: Víctor N
authors.initials: VN
authors.lastname: Suárez-Santiago
authors.forename: Maria J
authors.initials: MJ
authors.lastname: Salinas
authors.forename: Núria
authors.initials: N
authors.lastname: Garcia-Jacas
authors.forename: Pamela S
authors.initials: PS
authors.lastname: Soltis
authors.forename: Douglas E
authors.initials: DE
authors.lastname: Soltis
authors.forename: Gabriel
authors.initials: G
authors.lastname: Blanca
mesh_terms: D001482:Base Composition; D001483:Base Sequence; D031179:Centaurea / Q000235:genetics*; D019295:Computational Biology; D017931:DNA Primers; D021903:DNA, Ribosomal Spacer / Q000235:genetics; D003710:Demography; D019143:Evolution, Molecular; D014644:Genetic Variation; D005843:Geography; D006824:Hybridization, Genetic; D016013:Likelihood Functions; D019083:Mediterranean Region; D008957:Models, Genetic; D008969:Molecular Sequence Data; D010802:Phylogeny; D017422:Sequence Analysis, DNA
chemical_list: D017931:DNA Primers; D021903:DNA, Ribosomal Spacer