Reticulate evolution in the Acrolophus subgroup ( Centaurea L., Compositae) from the western Mediterranean: Origin and diversification of section Willkommia Blanca

• Published in: Molecular phylogenetics and evolution Vol. 43; no. 1; pp. 156 - 172
• Main Authors: Suárez-Santiago, Víctor N., Salinas, Maria J., Garcia-Jacas, Núria, Soltis, Pamela S., Soltis, Douglas E., Blanca, Gabriel
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.04.2007
• Subjects: Base Composition; Base Sequence; Centaurea; Centaurea - genetics; Compositae; Computational Biology; Concerted evolution; Demography; DNA Primers; DNA, Ribosomal Spacer - genetics; ETS; Evolution, Molecular; Genetic Variation; Geography; Hybridization, Genetic; ITS; Likelihood Functions; Mediterranean Region; Models, Genetic; Molecular Sequence Data; Nuclear ribosomal DNA; Phylogeny; Reticulate evolution; Sequence Analysis, DNA; Syngameon; Willkommia; Willkommia section; Mediterranean Region; Willkommia section; Syngameon; ETS; Nuclear ribosomal DNA; ITS; Compositae; Concerted evolution; Reticulate evolution; Centaurea
• ISSN: 1055-7903; 1095-9513
• DOI: 10.1016/j.ympev.2006.08.006

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.