title: Local Adaptation in European Firs Assessed through Extensive Sampling across Altitudinal Gradients in Southern Europe.
abstract: BACKGROUND
  Local adaptation is a key driver of phenotypic and genetic divergence at loci responsible for adaptive traits variations in forest tree populations. Its experimental assessment requires rigorous sampling strategies such as those involving population pairs replicated across broad spatial scales.
  
  
  METHODS
  A hierarchical Bayesian model of selection (HBM) that explicitly considers both the replication of the environmental contrast and the hierarchical genetic structure among replicated study sites is introduced. Its power was assessed through simulations and compared to classical 'within-site' approaches (FDIST, BAYESCAN) and a simplified, within-site, version of the model introduced here (SBM).
  
  
  RESULTS
  HBM demonstrates that hierarchical approaches are very powerful to detect replicated patterns of adaptive divergence with low false-discovery (FDR) and false-non-discovery (FNR) rates compared to the analysis of different sites separately through within-site approaches. The hypothesis of local adaptation to altitude was further addressed by analyzing replicated Abies alba population pairs (low and high elevations) across the species' southern distribution range, where the effects of climatic selection are expected to be the strongest. For comparison, a single population pair from the closely related species A. cephalonica was also analyzed. The hierarchical model did not detect any pattern of adaptive divergence to altitude replicated in the different study sites. Instead, idiosyncratic patterns of local adaptation among sites were detected by within-site approaches.
  
  
  CONCLUSIONS
  Hierarchical approaches may miss idiosyncratic patterns of adaptation among sites, and we strongly recommend the use of both hierarchical (multi-site) and classical (within-site) approaches when addressing the question of adaptation across broad spatial scales.
authors.affiliation: INRA, UR629 URFM Ecologie des Forêts Méditerranéennes, Domaine Saint Paul, Site Agroparc CS 40509, 84914 Avignon Cedex 9, France.|Institute of Biosciences and BioResources, National Research Council (IBBR-CNR), Division of Florence, Via Madonna del Piano 10, 50019 Sesto Fiorentino (FI), Italy.
authors.forename: Louise
authors.identifier: http://orcid.org/0000-0003-2769-2767
authors.initials: L
authors.lastname: Brousseau
authors.affiliation: Institute of Biosciences and BioResources, National Research Council (IBBR-CNR), Division of Florence, Via Madonna del Piano 10, 50019 Sesto Fiorentino (FI), Italy.|Scuola Superiore Sant'Anna, Piazza Martiri della Libertà 33, 56127 Pisa, Italy.|National Institute of Forest Research and Development (INCDS), Research Station Simeria, Str. Biscaria 1, 335900 Simeria, Romania.
authors.forename: Dragos
authors.initials: D
authors.lastname: Postolache
authors.affiliation: Department of Ecology and Genetics, Evolutionary Biology Center and Science for Life Laboratory, Uppsala University, 75236 Uppsala, Sweden.
authors.forename: Martin
authors.initials: M
authors.lastname: Lascoux
authors.affiliation: School of Biology, Aristotle University of Thessaloniki, GR-54124, Thessaloniki, Greece.
authors.forename: Andreas D
authors.initials: AD
authors.lastname: Drouzas
authors.affiliation: Department of Ecology and Genetics, Evolutionary Biology Center and Science for Life Laboratory, Uppsala University, 75236 Uppsala, Sweden.
authors.forename: Thomas
authors.initials: T
authors.lastname: Källman
authors.affiliation: Institute of Biosciences and BioResources, National Research Council (IBBR-CNR), Division of Florence, Via Madonna del Piano 10, 50019 Sesto Fiorentino (FI), Italy.|Institute of Biosciences and BioResources, National Research Council (IBBR-CNR), Division of Palermo, National 3. Research Council-Corso Calatafimi, 414-I-90129, Palermo (PA), Italy.
authors.forename: Cristina
authors.initials: C
authors.lastname: Leonarduzzi
authors.affiliation: University of Marburg, Faculty of Biology, Conservation Biology, Karl-von-Frisch-Straße 35032 Marburg, Germany.
authors.forename: Sascha
authors.initials: S
authors.lastname: Liepelt
authors.affiliation: Institute of Biosciences and BioResources, National Research Council (IBBR-CNR), Division of Florence, Via Madonna del Piano 10, 50019 Sesto Fiorentino (FI), Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Piotti
authors.affiliation: National Institute of Forest Research and Development (INCDS), Research Station Simeria, Str. Biscaria 1, 335900 Simeria, Romania.
authors.forename: Flaviu
authors.initials: F
authors.lastname: Popescu
authors.affiliation: University of Marburg, Faculty of Biology, Conservation Biology, Karl-von-Frisch-Straße 35032 Marburg, Germany.|Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Genebank Collections North, Inselstrasse 9, D-23999 Malchow/Poel, Germany.
authors.forename: Anna M
authors.initials: AM
authors.lastname: Roschanski
authors.affiliation: University of Forestry, 10, Kl. Ohridsky Blvd., 1797 Sofia, Bulgaria.
authors.forename: Peter
authors.initials: P
authors.lastname: Zhelev
authors.affiliation: INRA, UR629 URFM Ecologie des Forêts Méditerranéennes, Domaine Saint Paul, Site Agroparc CS 40509, 84914 Avignon Cedex 9, France.
authors.forename: Bruno
authors.initials: B
authors.lastname: Fady
authors.affiliation: Institute of Biosciences and BioResources, National Research Council (IBBR-CNR), Division of Florence, Via Madonna del Piano 10, 50019 Sesto Fiorentino (FI), Italy.
authors.forename: Giovanni Giuseppe
authors.initials: GG
authors.lastname: Vendramin
mesh_terms: D028202:Abies / Q000235:genetics*; D000222:Adaptation, Physiological / Q000235:genetics*; D000531:Altitude; D001499:Bayes Theorem; D002980:Climate; D003198:Computer Simulation; D018744:DNA, Plant / Q000235:genetics; D020224:Expressed Sequence Tags; D005787:Gene Frequency; D014644:Genetic Variation; D005838:Genotype; D005843:Geography; D010641:Phenotype; D020641:Polymorphism, Single Nucleotide; D014197:Trees / Q000235:genetics
chemical_list: D018744:DNA, Plant