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Träfflista för sökning "WFRF:(Wedin Mats) srt2:(2000-2004)"

Sökning: WFRF:(Wedin Mats) > (2000-2004)

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2.
  • Articus, Kristina, et al. (författare)
  • Phylogenetic studies in Usnea.
  • 2000
  • Ingår i: The Fourth IAL Symposium Progress and Problems in Lichenology at the Turn of the Millenium, Abstracts: 100. Barcelona..
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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3.
  • Articus, Kristina, 1971- (författare)
  • Phylogenetic Studies in Usnea (Parmeliaceae) and Allied Genera
  • 2004
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • This thesis deals with the phylogeny of the lichen genus Usnea (Parmeliaceae, Ascomycetes). The relationships and the morphological variation among Usnea species has been studied, as well as the relationship of Usnea to allied genera. Two species, U. florida and U. subfloridana, which earlier were regarded to form two separate species have been synonymized. In an analysis based on sequence data these two taxa formed a monophyletic group of intermixed specimens. Usnea florida and U. subfloridana have earlier been regarded to form a species pair, but the species pairs concept cannot be applied in this case. The morphological characters traditionally used for species recognition of a number of European Usnea species have been analyzed regarding their reliability. The evolution and distribution of the morphological characters was studied in relation to a phylogeny based on sequence data. Most characters proved to be homoplastic in relation to the phylogeny. Few characters were consistent in a clade, and the same character could be inconsistent in another clade. Therefore a combination of several characters is recommended for species recognition. The relationship of Neuropogon to Usnea was investigated based on sequence data. Neuropogon showed to be closely related to Usnea subg. Usnea. The subgenera Eumitria and Dolichousnea formed the sister group to the clade comprising subg. Usnea and Neuropogon. Usnea is paraphyletic in this investigation. Eumitria is treated as a genus and the subgenus Dolichousnea is elevated to generic rank. The position of Usnea, Neuropogon, Eumitria, and Dolichousnea in the family Parmeliaceae was investigated based on a phylogeny obtained by sequence data. Protousnea probably forms the sister group to the clade of Usnea, Neuropogon, Eumitria, and Dolichousnea. Several monophyletic groups in the family Parmeliaceae were identified.
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4.
  • Articus, Kristina, et al. (författare)
  • Ribosomal DNA and beta-tubulin data do not support the separation of the lichens Usnea florida and U-subfloridana as distinct species
  • 2002
  • Ingår i: Mycological Research. - 0953-7562 .- 1469-8102. ; 106, s. 412-418
  • Tidskriftsartikel (refereegranskat)abstract
    • The lichens Usnea florida and U. subfloridana have since long been recognised as distinct species. They show many similarities in morphology, but have different reproductive strategies. Usnea florida is always provided with many apothecia and produces no specialised asexual propagules. Usnea subfloridana has soralia, isidiomorphs and occasionally apothecia. Phylogenetic analyses based on continuous sequences of the ITS and LSU regions of the nuclear ribosomal DNA and the gene coding for beta-tubulin, show that specimens of the two species form one monophyletic group of intermixed specimens, and not two groups corresponding to morphology, which Would have been expected if two species were at hand. The 'species pair' concept in lichenology is discussed. Other Usnea species included in the study are: U. articulata, U. barbata, U. ceratina, U. filipendula. U. hirta, U. rigida and U. wasmuthii.
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6.
  • Lohtander, Katileena, 1966- (författare)
  • Phylogeny and species delimitation in Roccellaceae and Physciaceae (Euascomycetes)
  • 2000
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • DNA sequence data (the ITS region and Group I Introns) from the nuclear ribosomal repeat (rDNA), partial β-tubulin gene sequences, RAPD markers, and some morphological characters were analysed phylogenetically in order to examine relationships in lichenized Euascomycetes, from the species level to higher taxonomic levels. The species level studies comprise some so-called species pairs in two families, Roccellaceae (Arthoniales) and Physciaceae (Lecanorales). In order to determine whether the asexual specimens studied represent clonal species that have arisen from their fertile counterparts in a single event, or alternatively have multiple origins and are therefore conspecific, the ITS region, and in some cases the β-tubulin gene sequences and RAPD markers were obtained for several fertile and sterile specimens of various species pairs. A novel phylogenetic analysis of the species pair Phaeophyscia ciliata/P. orbicularis was introduced in this thesis. Molecular methods were also used to resolve the phylogeny of the family Physciaceae and the genus Physcia within it. The utility of indels (gaps) and different gap-coding in molecular data was also discussed.The DNA sequence data appeared to be informative. The ITS sequences provided abundant phylogenetic information at the family level, as well as at the genus and, in some cases, species levels. The intron positions varied between different genera and insertions were found to provide phylogenetic information mostly within and between species. The b-tubulin gene appeared to be an especially informative genetic marker at the species level.The results from the species pair studies indicated that the sexual and asexual specimens might be conspecific in many cases, since sexual and asexual counterparts were intermixed in the phylogenetic trees.
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