title: Multiple origin of metallicolous populations of the pseudometallophyte Arabidopsis halleri (Brassicaceae) in central Europe: the cpDNA testimony.
abstract: The population structure of the pseudo-metallophyte herb, Arabidopsis halleri, was studied using Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) on chloroplast DNA (cpDNA). The history of metallicolous (M) populations showing increased zinc tolerance was investigated. Eight primer-enzyme combinations out of 72 tested were applied to a total of 625 individuals from 28 widespread populations, 14 of them being M. Eleven distinct chlorotypes were found: five were common to nonmetallicolous (NM) and M populations, whereas six were only observed in one edaphic type (five in NM and one in M). No difference in chlorotype diversity between edaphic types was detected. Computed on the basis of chlorotype frequencies, the level of population differentiation was high but remained the same when taking into account levels of molecular divergence between chlorotypes. Isolation by distance was largely responsible for population differentiation. Geographically isolated groups of M populations were more genetically related to their closest NM populations than to each other. Our results suggest that M populations have been founded separately from distinct NM populations without suffering founding events and that the evolution towards increased tolerance observed in the distinct M population groups occurred independently.
authors.affiliation: Laboratoire de Génétique et Evolution des Populations Végétales, UMR CNRS 8016, FR CNRS 1818, Université des Sciences et Technologies de Lille, Bâtiment SN2, F-59655 Villeneuve d'Ascq cedex, France.
authors.forename: Maxime
authors.initials: M
authors.lastname: Pauwels
authors.forename: Pierre
authors.initials: P
authors.lastname: Saumitou-Laprade
authors.forename: Anne Catherine
authors.initials: AC
authors.lastname: Holl
authors.forename: Daniel
authors.initials: D
authors.lastname: Petit
authors.forename: Isabelle
authors.initials: I
authors.lastname: Bonnin
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics*; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D016000:Cluster Analysis; D018742:DNA, Chloroplast / Q000235:genetics; D005060:Europe; D014644:Genetic Variation; D005828:Genetics, Population; D005843:Geography; D006239:Haplotypes / Q000235:genetics; D008969:Molecular Sequence Data; D012150:Polymorphism, Restriction Fragment Length; D017422:Sequence Analysis, DNA; D015032:Zinc / Q000378:metabolism
chemical_list: D018742:DNA, Chloroplast; D015032:Zinc