J Syst Evol ›› 2017, Vol. 55 ›› Issue (4): 353-364.DOI: 10.1111/jse.12271

• Research Articles • Previous Articles     Next Articles

Neo- and Paleopolyploidy contribute to the species diversity of Asplenium—the most species-rich genus of ferns

Harald Schneider1,2*, Hong‐Mei Liu1, Yan‐Fen Chang1, Daniel Ohlsen3, Leon R. Perrie4, Lara Shepherd4, Michael Kessler5, Dirk Karger5,6, Sabine Hennequin7, Jeannine Marquardt2, Stephen Russell2, Stephen Ansell2, Ngan Thi Lu8, Peris Kamau9, Josmaily Lóriga Pineiro10, Ledis Regalado10,11, Jochen Heinrichs10, Atsushi Ebihara12, Alan R. Smith13, and Mary Gibby14   

  1. 1Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China
    2Department of Life Sciences, Natural History Museum, London SW7 5BD, UK
    3School of Botany, The University of Melbourne, Melbourne, Victoria 3010, Australia
    4Museum of New Zealand Te Papa Tongarewa, Wellington 6140, New Zealand
    5Institute of Systematic Botany, University of Zurich, 8008 Zurich, Switzerland
    6Dynamic Macroecology Group, Swiss Federal Research Institute WSL, 8903 Birmsersdorf, Switzerland
    7Institute de Systematique, Evolution, Biodiversite, Universite Pierre et Marie Curie, 75005 Paris, France
    8Department of Botany, Vietnam National Museum of Nature, Vietnam Academy of Science and Technology, Ha Noi, Vietnam
    9Botany Department, National Museums of Kenya, Nairobi, Kenya
    10University of Munich (LMU), Department of Biology I, Systematic Botany and Mycology, Geobio-Center, 80638 Munich, Germany 11Instituto de Ecologia y Sistematica, Carretera de Varona 11835 e/ Oriente y Lindero, Calabazar, Boyeros, La Habana, Cuba 12Department of Botany, National Museum of Nature and Science, Tsukuba 305-0005, Japan 13University Herbarium, University of California, Berkeley, CA 94720, USA 14Royal Botanic Garden Edinburgh, Edinburgh EH3 5LR, UK
  • Received:2017-05-20 Published:2017-07-24

Abstract: Polyploidy is widely considered as a major process in the evolution of plants but the accumulation of polyploid species diversity is still controversial. Some recent studies proposed increased extinction risk in neopolyploids compared with their diploid ancestors. The high proportion of polyploid ferns is expected to be formed mainly by neopolyploids, whereas paleopolyploid species are predicted to be clustered in clades founded by whole genome duplications. Here, we test this prediction by exploring the evolution of polyploidy in the derived fern family Aspleniaceae. The family has a global distribution and shows the highest frequency of polyploid taxa among all ferns. To test the hypothesis, we obtained a comprehensive phylogeny using chloroplast DNA sequences of 883 specimens representing 292 species. All published chromosome counts were mapped onto this phylogenetic framework in order to explore the evolution of polyploids. We recovered evidence for several whole genome duplications in the history of Aspleniaceae. Phylogenetic relationships of polyploids exceeding the tetraploid level suggest that tetraploid Asplenium species may have replaced their diploid ancestors as the main evolutionary players in some clades of this family.

Key words: chromosome number, diversification, extinction risk, genome evolution, macroevolution, neopolyploidy, paleopolyploidy