Anne-Laure Jacquemart

Multiple introductions boosted genetic diversity in the invasive range of black cherry (Prunus serotina; Rosaceae)

BACKGROUND AND AIMS Black cherry (Prunus serotina) is a North American tree that is rapidly invading European forests. This species was introduced first as an ornamental plant, then it was massively planted by foresters in many countries, but its origins and the process of invasion remain poorly documented. Based on a genetic survey of both native and invasive ranges, the invasion history of black cherry was investigated by identifying putative source populations and then assessing the importance of multiple introductions on the maintenance of gene diversity. METHODS Genetic variability and structure of 23 populations from the invasive range and 22 populations from the native range were analysed using eight nuclear microsatellite loci and five chloroplast DNA regions. KEY RESULTS Chloroplast DNA diversity suggests there were multiple introductions from a single geographic region (the north-eastern United States). A low reduction of genetic diversity was observed in the invasive range for both nuclear and plastid genomes. High propagule pressure including both the size and number of introductions shaped the genetic structure in Europe and boosted genetic diversity. Populations from Denmark, The Netherlands, Belgium and Germany showed high genetic diversity and low differentiation among populations, supporting the hypothesis that numerous introduction events, including multiple individuals and exchanges between sites, have taken place during two centuries of plantation. CONCLUSIONS This study postulates that the invasive black cherry has originated from east of the Appalachian Mountains (mainly the Allegheny plateau) and its invasiveness in north-western Europe is mainly due to multiple introductions containing high numbers of individuals.

Clonal structure in Vaccinium myrtillus L. revealed by RAPD and AFLP markers

The identification of clones and their spatial distribution is necessary to study the dynamics and evolution of clonal plant populations. Therefore, clonal structure of a Vaccinium myrtillus population was inferred from random amplified polymorphic DNA (RAPD) and amplified fragment length polymorphism (AFLP) markers. Among the 112 analyzed samples, 32 clones were identified. The results obtained with RAPDs and AFLPs were identical, showing that both molecular markers worked effectively in clone identification of bilberry. The population was clonally structured in the sense that the extent of clones was spatially limited; that is, clones formed discrete patches. However, the genetic distances between pairs of clones were not related to the spatial distances between them, indicating that the genetic variation among clones was distributed randomly in the studied area. The genotypic diversity ( \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape

Biological Flora of the British Isles : Vaccinium uliginosum L.

D=0.94

Patterns of allozymic variation within Calluna vulgaris populations at seed bank and adult stages

\end{document} ) and evenness ( \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape

Patterns of chloroplast diversity among western European Dactylorhiza species (Orchidaceae)

E=0.92

Reproductive biology of the andromonoecious Cucumis melo subsp agrestis (Cucurbitaceae)

\end{document} ) observed in V. myrtillus were similar to other Ericaceae species. The observed relationship between the mean similarity index calculated between clones and the outcrossing rate of Ericaceous species indicates that this mean similarity index could be used as a rough estimator of the mating system of plant species.