Intriguing small-scale spatial distribution of chloropastic and nuclear diversity in the endangered plant Biscutella neustriaca (Brassicaceae)
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Biscutella neustriaca is an isolated plant taxon with about three thousand known individuals distributed in several fragmented populations. Despite its status as an endangered plant subject to a European LIFE programme for its protection, no conclusive genetic analysis has been performed to help its conservation. We analysed the genetic variability and distribution of nuclear microsatellite markers in a large sample of the population, as well as of the MatK chloroplastic gene in a subsample. We showed, first, that both pollen and seed dispersal, as well as clonal reproduction are strongly limited, and the mating system is obligate outcrossing. Second, we detected two highly divergent chloroplast haplogroups, as well as two completely distinct nuclear gene pools suggesting an ancient isolation between two groups of populations. Intriguingly, a third group of populations appears to combine the nuclear gene pool of one group with the chloroplast haplotype of the other group, suggesting a more recent dramatic colonization and foundation event. Thanks to complementary geological and historical data, we propose a scenario for the evolutionary history of this metapopulation influenced by the dynamics of Seine meanders and human activities. Finally, we give some suggestions for future conservation actions.
KeywordsConservation genetics Genetic structure Admixture Local adaptation
We wish to thank Pierre Saumitou-Laprade for his help establishing the microsatellite library; Julie Lemire, Antoine Tresca, Emmanuelle Bernet, Carine Douville, Emmanuel Vochelet, Margherita Lega, Eric Schmitt, Nathalie Faure, Isabelle de Cauwer, Benoit Leducq and Julien Bouchet for their help during sampling trips; Alain Durand, Jean-Pierre Coutard, and Nicole Limondin-Lozouet for their help in collecting geological information; Betty Courquin for discussions; Mary Thaler and two anonymous reviewers for helpful comments, and the Archives Départementales d’Evreux (Normandy, France) for providing documents about the Saint-Pierre-Louvier-Les-Andelys railway construction.
- Bonnet E (1879) Biscutella neustriaca-Bulletin de la Société Dauphinoise pour l'Échange des Plantes 6:222Google Scholar
- Goudet J (1995) FSTAT (Version 1.2): a computer program to calculate F-statistics. J Hered 86:485–486Google Scholar
- Lécolle F (1989) Le cours moyen de la Seine au Pléistocène moyen et supérieur—Géologie et Préhistoire. Groupe Seine—Laboratoire de Géologie—Université de Rouen, RouenGoogle Scholar
- Lemey P, Rambaut A, Welch JJ, Suchard MA (2010) Phylogeography takes a relaxed random walk in continuous space and time. Mol Biol Evol 27:1877–1885Google Scholar
- Olowokudejo JD (1992) Taxonomic significance of leaf indumentum characteristics of the genus Biscutella (Cruciferae). Folia Geobot Phytotaxon 27:401–407Google Scholar