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Felber, François

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Felber, François
Affiliation principale
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https://libra.unine.ch/handle/123456789/30618

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  • Publication
    Accès libre
    Spontaneous gene flow and population structure in wild and cultivated chicory, Cichorium intybus L.
    (2008)
    Kiær, L. P.
    ;
    Felber, François 
    ;
    Flavell, A.
    ;
    Guadagnuolo, Roberto
    ;
    Guiatti, D.
    ;
    Hauser, T. P.
    ;
    Olivieri, A. M.
    ;
    Scotti, I.
    ;
    Syed, N.
    ;
    Vischi, M.
    ;
    van de Wiel, C.
    ;
    Jørgensen, R. B.
    Spontaneous gene flow between wild and cultivated chicory, Cichorium intybus L. , may have implications for the genetic structure and evolution of populations and varieties. One aspect of this crop-wild gene flow is the dispersal of transgenes from genetically modified varieties, e.g. gene flow from GM chicory to natural chicory could have unwanted consequences. With the purpose to identify and quantify crop-wild gene flow in chicory, we analysed introgression in 19 wild chicory populations and 16 accessions of chicory varieties and landraces distributed across Northern, Central and Mediterranean Europe. The analysis used 281 AFLP markers and 75 SSAP markers giving a total of 356 polymorphic markers. Results from model based assignments with the program STRUCTURE indicated many incidents of recent gene flow. Gene flow was observed both between cultivars and wild populations, between landraces and wild populations, between different wild populations as well as between cultivars. Population structure visualized by distance-based clustering showed a North–South geographical structuring of the wild populations, and a general grouping of the cultivars corresponding to known origin. The results indicated, however, that the structuring between the two groups of wild and cultivated types was weak. As crop and wild recipients are genetically close and genes are transferred between the two types rather frequently, focus on mitigating crop-wild gene flow should be increased, before transgenic varieties are cultivated openly.
  • Publication
    Accès libre
    Search for evidence of introgression of wheat (Triticum aestivum L.) traits into sea barley (Hordeum marinum s.str. Huds.) and bearded wheatgrass (Elymus caninus L.) in central and northern Europe, using isozymes, RAPD and microsatellite markers
    (2001)
    Guadagnuolo, Roberto
    ;
    Savova Bianchi, Dessislava 
    ;
    Keller-Senften, J.
    ;
    Felber, François 
    Seeds of English and Austrian populations of bearded wheatgrass (Elymus caninus L.) and sea barley (Hordeum marinum Huds.) growing in the vicinity of wheat (Triticum aestivum L.) fields were collected in order to search for evidence of the introgression of wheat traits into these wild relatives. Seeds were sown and plants grown for subsequent analyses using morphological and genetic (isozymes, RAPD and wheat microsatellites) markers. No F1 hybrids were found within the individuals of the two species grown, neither with morphological nor with genetic markers. Also, no evidence of introgression of wheat traits into E. caninus was observed. However, in one individual of H. marinum which had the typical morphology of this species, numerous species-specific DNA markers of wheat were amplified, thereby demonstrating previous hybridization. Consequently, the hybridization between wheat and H. marinum under natural conditions and the introgression of wheat traits into this wild relative seems to be possible. Our results contribute to the risk assessment of transgenic wheat cultivation.
  • Publication
    Accès libre
    Specific genetic markers for wheat, spelt, and four wild relatives: comparison of isozymes, RAPDs, and wheat microsatellites
    (2001)
    Guadagnuolo, Roberto
    ;
    Savova Bianchi, Dessislava 
    ;
    Felber, François 
    Trois types de marqueurs—les isozymes, les RAPDs (« random amplified polymorphic DNAs ») et les microsatellites du blé—ont été testés sur six espèces appartenant à la tribu des Triticeae, le blé, l'épeautre et quatre espèces sauvages apparentées (Aegilops cylindrica, Elymus caninus, Hordeum marinum et Agropyron junceum). Le but de l'étude était d'évaluer leur capacité de générer des marqueurs spécifiques pour la différenciation des espèces cultivées et sauvages. Les marqueurs ont été produits afin de pouvoir détecter ultérieurement de l'introgression d'ADN du blé dans les espèces apparentées. Tous les types de marqueurs ont permis de séparer les espèces cultivées des sauvages. Les microsatellites du blé n'ont pas été amplifiés dans toutes les espèces sauvages, alors que les RAPDs et les isozymes ont détecté du polymorphisme chez toutes les espèces. Les dendrogrammes obtenus à partir des données RAPD et isozymes distinguaient les variétés de blé autrichienne et anglaises des suisses, alors qu'aucune séparation entre blé et épeautre suisses n'y était observée. Une légère discrimination entre populations anglaises et autrichiennes d'E. caninus a été obtenue avec les marqueurs RAPD. Les populations d'Ae. cylindricaétaient séparées dans le dendrogramme obtenu avec les microsatellites du blé, alors que ce dernier groupait H. marinum et E. caninus. Les matrices de similarité basées sur les trois types de marqueurs étaient fortement corrélées. La valeur la plus élevée a été obtenue entre la matrice des RAPD et celle des isozymes (test de Mantel, r = 0,93). Entre la matrice basée sur les microsatellites et celles basées sur les RAPD et les isozymes, la corrélation était plus faible, 0,74 et 0,68 respectivement. Alors que les microsatellites sont très utiles pour la comparaison de lignées fortement apparentées, ils sont moins appropriés pour l'étude de taxons relativement éloignés. Les isozymes peuvent générer suffisamment de marqueurs pour différencier les espèces, mais ils sont moins adaptés pour l'étude de la diversité génétique intraspécifique. Les RAPDs peuvent produire un grand nombre de marqueurs utiles pour l'étude de la diversité inter- et intra-spécifique, plus rapidement et facilement que les isozymes et les microsatellites., Three types of markers—isozymes, RAPDs (random amplified polymorphic DNAs), and wheat microsatellites—were tested on wheat, spelt, and four wild wheat relatives (Aegilops cylindrica, Elymus caninus, Hordeum marinum, and Agropyron junceum). The aim was to evaluate their capability to provide specific markers for differentiation of the cultivated and wild species. The markers were set up for subsequent detection of hybrids and introgression of wheat DNA into wild relatives. All markers allowed differentiation of the cultivated from the wild species. Wheat microsatellites were not amplified in all the wild relatives, whereas RAPDs and isozymes exhibited polymorphism for all species. The dendrograms obtained with RAPD and isozyme data separated Swiss wheat cultivars from those collected in Austria and England, while no difference was found between Swiss spelt and wheat. RAPD data provided a weak discrimination between English and Austrian E. caninus. The microsatellite-based dendrogram discriminated populations of Ae. cylindrica, but no clear separation of H. marinum from E. caninus was revealed. The similarity matrices based on the three different sets of data were strongly correlated. The highest value was recorded between the matrices based on RAPDs and isozymes (Mantel's test, r = 0.93). Correlations between the similarity matrix based on microsatellites and matrices based on RAPDs and isozymes were lower: 0.74 and 0.68, respectively. While microsatellites are very useful for comparisons of closely related accessions, they are less suitable for studies involving less-related taxa. Isozymes provide interesting markers for species differentiation, but their use seems less appropriate for studies of within-species genetic variation. RAPDs can produce a large set of markers, which can be used for the evaluation of both between- and within-species genetic variation, more rapidly and easily than isozymes and microsatellites.
  • Publication
    Accès libre
    Sensitivity of plant and soil ecosystems of the Alps to climate change
    (Boston: MIT Press, 1998)
    Theurillat, Jean-Paul
    ;
    Felber, François 
    ;
    Geissler, Patricia
    ;
    Gobat, Jean-Michel 
    ;
    Fierz, Marlyse
    ;
    Fischlin, Andreas
    ;
    Küpfer, Philippe 
    ;
    Schlüssel, André
    ;
    Velutti, Caterina
    ;
    Zhao, Gui-Fang
    ;
    Cebon, Peter
    ;
    Dahinden, Urs
    ;
    Davies, Huw
    ;
    Imboden, Dieter
    ;
    Jaeger, Carlo