000028384 001__ 28384
000028384 005__ 20150420164327.0
000028384 0248_ $$aoai:doc.rero.ch:20120131122704-JW$$punifr$$ppostprint$$prero_explore$$particle$$zthesis_urn$$zreport$$zthesis$$zbook$$zjournal$$zcdu574$$zcdu16$$zpreprint$$zcdu1$$zdissertation$$zcdu34
000028384 041__ $$aeng
000028384 080__ $$a574
000028384 100__ $$aMráz, Patrik$$uDepartment of Biology, Unit of Ecology & Evolution, University of Fribourg, Switzerland
000028384 245__ $$9eng$$aAllopolyploid origin of highly invasive Centaurea stoebe s.l. (Asteraceae)
000028384 269__ $$c2011-11-20
000028384 520__ $$9eng$$aSpotted knapweed (Centaurea stoebe) occurs from Western Asia to Western Europe both as diploid and tetraploid cytotypes, predominantly in single-cytotype populations with higher frequency of diploid populations. Interestingly, only tetraploids have been recorded so far from its introduced range in North America where they became highly invasive.  We performed phylogenetic and network analyses of more than 40 accessions of the C. stoebe and C. paniculata groups and other related taxa using cloned internal transcribed spacer (ITS) and sequences of the chloroplast trnT–trnL and atpBrbcL regions to (i) assess the evolutionary origin of tetraploid C. stoebe s.l., and (ii) uncover the phylogeny of the C. stoebe group. Both issues have not been studied so far and thus remained controversial.  Cloned ITS sequences showed the presence of two slightly divergent ribotypes occurring in tetraploid cytotype, while only one major ribotype was present in diploid C. stoebe s.str. This pattern suggests an allopolyploid origin of tetraploids with contribution of the diploid C. stoebe s.str. genome. Although we were not able to detect the second parental taxon, we hypothesize that hybridization might have triggered important changes in morphology and life history traits, which in turn may explain the colonization success of the tetraploid taxon. Bayesian relaxed clock estimations indicate a relatively recent – Pleistocene origin of the tetraploid C. stoebe s.l. Furthermore, our analyses showed a deep split between the C. paniculata and C. stoebe groups, and a young diversification of the taxa within the C. stoebe group. In contrast to nrDNA analyses, the observed pattern based on two cpDNA regions was inconclusive with respect to the origin and phylogeny of the studied taxa, most likely due to shared ancient polymorphism and frequent homoplasies.
000028384 695__ $$9eng$$aAllopolyploidy ; Centaurea maculosa ; cpDNA ; Flow cytometry ; Invasion ; ITS ; Hybridization ; Life history traits ; nrDNA ; Polyploidy
000028384 700__ $$aGarcia-Jacas, Núria$$uBotanic Institute of Barcelona (IBB-CSIC-ICUB), Barcelona, Spain
000028384 700__ $$aGex-Fabry, Emilie$$uDepartment of Biology, Unit of Ecology & Evolution, University of Fribourg, Switzerland
000028384 700__ $$aSusanna, Alfonso$$uBotanic Institute of Barcelona (IBB-CSIC-ICUB), Barcelona, Spain
000028384 700__ $$aBarres, Laia$$uBotanic Institute of Barcelona (IBB-CSIC-ICUB), Barcelona, Spain
000028384 700__ $$aMüller-Schärer, Heinz$$uDepartment of Biology, Unit of Ecology & Evolution, University of Fribourg, Switzerland
000028384 773__ $$g2012/62/2/612–623$$tMolecular Phylogenetics and Evolution
000028384 775__ $$gPublished version$$ohttp://dx.doi.org/10.1016/j.ympev.2011.11.006
000028384 8564_ $$fmra_aoh.pdf$$qapplication/pdf$$s834247$$uhttp://doc.rero.ch/record/28384/files/mra_aoh.pdf$$yorder:1$$zpdf
000028384 918__ $$aFaculté des sciences$$bDécanat, Ch. du Musée 6A, 1700 Fribourg$$cBiologie
000028384 919__ $$aUniversité de Fribourg$$bFribourg$$ddoc.support@rero.ch
000028384 980__ $$aPOSTPRINT$$bUNIFR$$fART_JOURNAL
000028384 990__ $$a20120131122704-JW