Footprints of past intensive diversification and structuring in the genus Zelkova (Ulmaceae) in south-western Eurasia

Authors

  • Camille Christe,

    1. Plant Systematics and Biodiversity Laboratory, Molecular Phylogeny and Genetics Unit, Conservatoire et Jardin botaniques de la Ville de Genève, Geneva, Switzerland
    2. Department of Biology and Botanic Garden, University of Fribourg, Fribourg, Switzerland
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  • Gregor Kozlowski,

    1. Department of Biology and Botanic Garden, University of Fribourg, Fribourg, Switzerland
    2. Natural History Museum, Fribourg, Switzerland
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  • David Frey,

    1. Department of Biology and Botanic Garden, University of Fribourg, Fribourg, Switzerland
    2. Conservation Biogeography Group, Department of Geosciences, University of Fribourg, Fribourg, Switzerland
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  • Sébastien Bétrisey,

    1. Department of Biology and Botanic Garden, University of Fribourg, Fribourg, Switzerland
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  • Elmira Maharramova,

    1. Institute of Botany, Azerbaijan National Academy of Sciences, Baku, Azerbaijan
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  • Giuseppe Garfì,

    1. National Research Council (CNR), Institute of Biosciences and Bioresources, Palermo, Italy
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  • Stergios Pirintsos,

    1. Department of Biology, University of Crete, Crete, Greece
    2. Botanical Garden, University of Crete, Crete, Greece
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  • Yamama Naciri

    Corresponding author
    1. Plant Systematics and Biodiversity Laboratory, Molecular Phylogeny and Genetics Unit, Conservatoire et Jardin botaniques de la Ville de Genève, Geneva, Switzerland
    2. Plant Systematics and Biodiversity Laboratory, University of Geneva, Geneva, Switzerland
    • Correspondence: Yamama Naciri, Laboratoire de Systématique Végétale et Biodiversité, Unité de Phylogénie et Génétique Moléculaires, Conservatoire et Jardin botaniques, 1292 Chambésy, Geneva, Switzerland.

      E-mail: Yamama.Naciri@ville-ge.ch

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Abstract

Aim

To elucidate the phylogeographical patterns in three Cenozoic relict species: Zelkova sicula, Z. abelicea and Z. carpinifolia (Ulmaceae).

Location

Sicily, Crete and Transcaucasia.

Methods

Two chloroplast loci (trnH–psbA and trnL) and the nuclear ribosomal markers ITS1 and ITS2 were sequenced for 154 samples collected from 14 populations of Z. abelicea, 16 populations of Z. carpinifolia, and the two known populations of Z. sicula. We obtained georeferenced data, calculated median joining networks and carried out diversity analyses. A few ex situ samples collected from botanical gardens, of the East Asian species Zelkova serrata, Z. schneideriana and Z. sinica, were also analysed for comparative purposes.

Results

High levels of variability were found in the chloroplast markers within Z. carpinifolia (15 haplotypes) and Z. abelicea (33 haplotypes), in association with strong phylogeographical structure. Conversely, Z. sicula was characterized by low diversity, with each population exhibiting a single haplotype. Lower variability was found for ITS1 and ITS2 within Z. carpinifolia and Z. abelicea (13 and 7 ribotypes per species, respectively), with Z. carpinifolia showing a high proportion of populations with no intragenomic polymorphism. In the triploid and clonal Z. sicula, all individuals displayed intragenomic polymorphism and seven ribotypes were identified.

Main conclusions

The chloroplast diversity of Z. abelicea and Z. carpinifolia suggests a very ancient history of diversification and structuring, with footprints of past expansions and more recent bottlenecks. Zelkova sicula has had a history of severe isolation and is likely to be of hybrid origin.

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