title: Population genomics of an endemic Mediterranean fish: differentiation by fine scale dispersal and adaptation.
abstract: The assessment of the genetic structuring of biodiversity is crucial for management and conservation. For species with large effective population sizes a low number of markers may fail to identify population structure. A solution of this shortcoming can be high-throughput sequencing that allows genotyping thousands of markers on a genome-wide approach while facilitating the detection of genetic structuring shaped by selection. We used Genotyping-by-Sequencing (GBS) on 176 individuals of the endemic East Atlantic peacock wrasse (Symphodus tinca), from 6 locations in the Adriatic and Ionian seas. We obtained a total of 4,155 polymorphic SNPs and we observed two strong barriers to gene flow. The first one differentiated Tremiti Islands, in the northwest, from all the other locations while the second one separated east and south-west localities. Outlier SNPs potentially under positive selection and neutral SNPs both showed similar patterns of structuring, although finer scale differentiation was unveiled with outlier loci. Our results reflect the complexity of population genetic structure and demonstrate that both habitat fragmentation and positive selection are on play. This complexity should be considered in biodiversity assessments of different taxa, including non-model yet ecologically relevant organisms.
authors.affiliation: Departament de Genètica, Microbiologia i Estadística and IRBio, Universitat de Barcelona, Av.Diagonal 643, 08028 Barcelona, Spain.
authors.forename: Carlos
authors.initials: C
authors.lastname: Carreras
authors.affiliation: Departament de Genètica, Microbiologia i Estadística and IRBio, Universitat de Barcelona, Av.Diagonal 643, 08028 Barcelona, Spain.
authors.forename: Víctor
authors.initials: V
authors.lastname: Ordóñez
authors.affiliation: Department of Biology, University of Padova, via G. Colombo 3, 35131 Padova, Italy.|Consorzio Nazionale Interuniversitario per le Scienze del Mare, Piazzale Flaminio 9, 00196 Roma, Italy.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Zane
authors.affiliation: University of Zadar, Ul. Mihovila Pavlinovica, 23000 Zadar, Croatia.
authors.forename: Claudia
authors.initials: C
authors.lastname: Kruschel
authors.affiliation: Department of Biology, Faculty of Technical Sciences, Vlora University, 9401 Vlora, Albania.
authors.forename: Ina
authors.initials: I
authors.lastname: Nasto
authors.affiliation: Centre d'Estudis Avançats de Blanes (CEAB-CSIC), Car. Acc. Cala St. Francesc 14, 17300 Blanes Girona, Spain.
authors.forename: Enrique
authors.initials: E
authors.lastname: Macpherson
authors.affiliation: Departament de Genètica, Microbiologia i Estadística and IRBio, Universitat de Barcelona, Av.Diagonal 643, 08028 Barcelona, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Pascual
mesh_terms: D000222:Adaptation, Physiological; D063147:Animal Distribution; D000818:Animals; D051456:Gene Flow; D005828:Genetics, Population; D016678:Genome; D005838:Genotype; D008522:Mediterranean Sea; D010473:Perciformes / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D017422:Sequence Analysis, DNA