title: Genome size shifts: karyotype evolution in Crepis section Neglectoides (Asteraceae).
abstract: Plant genome size evolution is a very dynamic process: the ancestral genome of angiosperms was initially most likely small, which led to a tendency towards genome increase during evolution. However, findings in several angiosperm lineages demonstrate mechanisms that also led to genome size contraction. Recent molecular investigations on the Asteraceae genus Crepis suggest that several genomic reduction events have occurred during the evolution of the genus. This study focuses on the Mediterranean Crepis sect. Neglectoides, which includes three species with some of the smallest genomes within the whole genus. Crepis neglecta has the largest genome in sect. Neglectoides, approximately twice the size of the two species Crepis cretica and Crepis hellenica. Whereas C. cretica and C. hellencia are more closely related to each other than to C. neglecta the karyotypes of the latter species and C. cretica are similar, while that of C. hellenica differs considerably. Here, the karyotypic organisation of the three species is investigated with fluorescence in-situ hybridisation and studied in a molecular phylogenetic framework based on the nuclear markers Actin, CHR12, CPN60B, GPCR1 and XTH23. Our findings further corroborate the occurrence of genome size contraction in Crepis, and suggest that the difference in genome size between C. neglecta and C. cretica is mostly due to elimination of dispersed repetitive elements, whereas chromosomal reorganisation was involved in the karyotype formation of C. hellenica.
authors: Botanic Garden and Botanical Museum Berlin-Dahlem, Freie Universität Berlin, Berlin, Germany.|Dahlem Centre of Plant Sciences, Freie Universität Berlin, Berlin, Germany.
authors: N
authors: N
authors: Enke
authors: Dahlem Centre of Plant Sciences, Freie Universität Berlin, Berlin, Germany.|Institut für Biologie - Angewandte Genetik, Freie Universität Berlin, Berlin, Germany.
authors: R
authors: R
authors: Kunze
authors: CNRS, Laboratoire Ecologie, Systématique et Evolution, UMR 8079, Université Paris Sud, Orsay, France.|Faculty of Forestry, University of Sarajevo, Sarajevo, Bosnia and Herzegovina.
authors: F
authors: F
authors: Pustahija
authors: Institute for Biochemistry I, Medical Faculty, University of Cologne, Cologne, Germany.|Molecular Biology Group, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany.
authors: G
authors: G
authors: Glöckner
authors: Botanic Garden and Botanical Museum Berlin-Dahlem, Freie Universität Berlin, Berlin, Germany.|AG Spezielle Botanik, Justus-Liebig-Universität Giessen, Giessen, Germany.
authors: J
authors: J
authors: Zimmermann
authors: Dahlem Centre of Plant Sciences, Freie Universität Berlin, Berlin, Germany.|Institut für Biologie - Angewandte Genetik, Freie Universität Berlin, Berlin, Germany.
authors: J
authors: J
authors: Oberländer
authors: Department of Biology, Botanical Institute, University of Patras, Patras, Greece.
authors: G
authors: G
authors: Kamari
authors: CNRS, Laboratoire Ecologie, Systématique et Evolution, UMR 8079, Université Paris Sud, Orsay, France.
authors: S
authors: S
authors: Siljak-Yakovlev
mesh_terms: D001483:Base Sequence; D002871:Chromosome Banding; D032461:Chromosomes, Plant / Q000235:genetics*; D027468:Crepis / Q000166:cytology / Q000235:genetics*; D018744:DNA, Plant / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D019143:Evolution, Molecular; D005819:Genetic Markers / Q000235:genetics; D059646:Genome Size; D018745:Genome, Plant / Q000235:genetics*; D017404:In Situ Hybridization, Fluorescence; D059785:Karyotype; D008969:Molecular Sequence Data; D010802:Phylogeny; D017422:Sequence Analysis, DNA
chemical_list: D018744:DNA, Plant; D004275:DNA, Ribosomal; D005819:Genetic Markers
keywords: Crepis; fluorescence in situ hybridisation; fluorochrome banding; genome size; heterochromatin and rDNA physical mapping; molecular phylogeny; nuclear single or low copy genes