title: Key processes for Cheirolophus (Asteraceae) diversification on oceanic islands inferred from AFLP data.
abstract: The radiation of the genus Cheirolophus (Asteraceae) in Macaronesia constitutes a spectacular case of rapid diversification on oceanic islands. Twenty species - nine of them included in the IUCN Red List of Threatened Species - have been described to date inhabiting the Madeiran and Canarian archipelagos. A previous phylogenetic study revealed that the diversification of Cheirolophus in Macaronesia started less than 2 Ma. As a result of such an explosive speciation process, limited phylogenetic resolution was reported, mainly due to the low variability of the employed molecular markers. In the present study, we used highly polymorphic AFLP markers to i) evaluate species' boundaries, ii) infer their evolutionary relationships and iii) investigate the patterns of genetic diversity in relation to the potential processes likely involved in the radiation of Cheirolophus. One hundred and seventy-two individuals representing all Macaronesian Cheirolophus species were analysed using 249 AFLP loci. Our results suggest that geographic isolation played an important role in this radiation process. This was likely driven by the combination of poor gene flow capacity and a good ability for sporadic long-distance colonisations. In addition, we also found some traces of introgression and incipient ecological adaptation, which could have further enhanced the extraordinary diversification of Cheirolophus in Macaronesia. Last, we hypothesize that current threat categories assigned to Macaronesian Cheirolophus species do not reflect their respective evolutionary relevance, so future evaluations of their conservation status should take into account the results presented here.
authors.affiliation: Laboratori de Botànica - Unitat associada CSIC, Facultat de Farmàcia, Universitat de Barcelona, Barcelona, Catalonia, Spain.
authors.forename: Daniel
authors.initials: D
authors.lastname: Vitales
authors.affiliation: Institut Botànic de Barcelona (IBB-CSIC-ICUB), Barcelona, Catalonia, Spain; Área de Biodiversidad y Conservación, Universidad Rey Juan Carlos, Móstoles, Madrid, Spain.
authors.forename: Alfredo
authors.initials: A
authors.lastname: García-Fernández
authors.affiliation: Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond, Surrey, United Kingdom.
authors.forename: Jaume
authors.initials: J
authors.lastname: Pellicer
authors.affiliation: Laboratori de Botànica - Unitat associada CSIC, Facultat de Farmàcia, Universitat de Barcelona, Barcelona, Catalonia, Spain.
authors.forename: Joan
authors.initials: J
authors.lastname: Vallès
authors.affiliation: Unidad de Botánica-ICIA, Puerto de la Cruz, Canary Islands, Spain.
authors.forename: Arnoldo
authors.initials: A
authors.lastname: Santos-Guerra
authors.affiliation: Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond, Surrey, United Kingdom.
authors.forename: Robyn S
authors.initials: RS
authors.lastname: Cowan
authors.affiliation: Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond, Surrey, United Kingdom.
authors.forename: Michael F
authors.initials: MF
authors.lastname: Fay
authors.affiliation: Laboratori de Botànica - Unitat associada CSIC, Facultat de Farmàcia, Universitat de Barcelona, Barcelona, Catalonia, Spain; Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond, Surrey, United Kingdom.
authors.forename: Oriane
authors.initials: O
authors.lastname: Hidalgo
authors.affiliation: Institut Botànic de Barcelona (IBB-CSIC-ICUB), Barcelona, Catalonia, Spain.
authors.forename: Teresa
authors.initials: T
authors.lastname: Garnatje
mesh_terms: D054458:Amplified Fragment Length Polymorphism Analysis / Q000379:methods*; D019659:Asteraceae / Q000145:classification* / Q000235:genetics*; D001499:Bayes Theorem; D044822:Biodiversity; D005075:Biological Evolution; D018744:DNA, Plant / Q000032:analysis*; D051456:Gene Flow; D049810:Genetic Speciation; D014644:Genetic Variation; D010802:Phylogeny; D013030:Spain
chemical_list: D018744:DNA, Plant