title: Panmixia and dispersal from the Mediterranean Basin to Macaronesian Islands of a macrolichen species.
abstract: The Mediterranean region, comprising the Mediterranean Basin and the Macaronesian Islands, represents a center of diversification for many organisms. The genetic structure and connectivity of mainland and island microbial populations has been poorly explored, in particular in the case of symbiotic fungi. Here we investigated genetic diversity and spatial structure of the obligate outcrossing lichen-forming fungus Parmelina carporrhizans in the Mediterranean region. Using eight microsatellite and mating-type markers we showed that fungal populations are highly diverse but lack spatial structure. This is likely due to high connectivity and long distance dispersal of fungal spores. Consistent with low levels of linkage disequilibrium and lack of clonality, we detected both mating-type idiomorphs in all populations. Furthermore we showed that the Macaronesian Islands are the result of colonization from the Mediterranean Basin. The unidirectional gene flow, though, seemed not to be sufficient to counterbalance the effects of drift, resulting in comparatively allelic poor peripheral populations. Our study is the first to shed light on the high connectivity and lack of population structure in natural populations of a strictly sexual lichen fungus. Our data further support the view of the Macaronesian Islands as the end of the colonization road for this symbiotic ascomycete.
authors.affiliation: Departamento de Biología Vegetal II, Facultad de Farmacia, Universidad Complutense de Madrid, 28040 Madrid, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Alors
authors.affiliation: Senckenberg Biodiversity and Climate Research Centre (BiK-F), Senckenberganlage 25, 60325 Frankfurt am Main, Germany.
authors.forename: Francesco Dal
authors.initials: FD
authors.lastname: Grande
authors.affiliation: Departamento de Biología Vegetal II, Facultad de Farmacia, Universidad Complutense de Madrid, 28040 Madrid, Spain.
authors.forename: Paloma
authors.initials: P
authors.lastname: Cubas
authors.affiliation: Departamento de Biología Vegetal II, Facultad de Farmacia, Universidad Complutense de Madrid, 28040 Madrid, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Crespo
authors.affiliation: Senckenberg Biodiversity and Climate Research Centre (BiK-F), Senckenberganlage 25, 60325 Frankfurt am Main, Germany.|Institute of Ecology, Evolution and Diversity, Goethe Universität, Max-von-Laue-Str. 13, D-60438 Frankfurt, Germany.
authors.forename: Imke
authors.initials: I
authors.lastname: Schmitt
authors.affiliation: Departamento de Biología y Geología, Física y Química Inorgánica (Área de Biodiversidad y Conservación), ESCET, Universidad Rey Juan Carlos, Móstoles, 28933 Madrid, Spain.
authors.forename: M Carmen
authors.initials: MC
authors.lastname: Molina
authors.affiliation: Departamento de Biología Vegetal II, Facultad de Farmacia, Universidad Complutense de Madrid, 28040 Madrid, Spain.
authors.forename: Pradeep K
authors.initials: PK
authors.lastname: Divakar
mesh_terms: D016002:Discriminant Analysis; D051456:Gene Flow; D014644:Genetic Variation; D062312:Islands; D008011:Lichens / Q000382:microbiology*; D019083:Mediterranean Region; D018895:Microsatellite Repeats / Q000235:genetics; D000068837:Parmeliaceae / Q000235:genetics* / Q000502:physiology; D025341:Principal Component Analysis; D013172:Spores, Fungal / Q000235:genetics