Sökning: "introgression"

Visar resultat 26 - 30 av 45 avhandlingar innehållade ordet introgression.

  1. 26. Systematics of polyploid Dactylorhiza (Orchidaceae) - genetic diversity, phylogeography and evolution

    Författare :Sofie Olofsson; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; microsatellites; allozymes; ITS; plastid DNA; Dactylorhiza majalis ssp. traunsteineri; allopolyploidy; AFLPs; immigration history; diploidization; hybridization;

    Sammanfattning : This thesis examines genetic variation in allotetraploids of the Dactylorhiza incarnata/maculata polyploid complex in different parts of Europe. The molecular markers used were AFLPs, allozymes, ITS, nuclear microsatellites and plastid DNA markers. LÄS MER

  3. 27. Genetic, morphological and chemical variation in the genus Harpagophytum

    Författare :Mbaki Muzila; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : Harpagophytum procumbens is a valuable medicinal plant but mistakes with plant identification at harvesting, and wilful adulteration using the presumably less efficient H. zeyheri are suggested. A multidisciplinary study with plant material from Botswana was conducted. LÄS MER

  4. 28. Sexual Signals and Speciation : A Study of the Pied and Collared Flycatcher

    Författare :Jon Haavie; Glenn-Peter Saetre; Trevor Price; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Biology; Speciation; Sexual signals; Hybridization; Reinforcement; Song; Female preference; Sex-linkage; Biologi; Biology; Biologi;

    Sammanfattning : Speciation is the process in which reproductive barriers evolve between populations. In this thesis I examine how sexual signals contribute to the maintenance, reinforcement or breakdown of reproductive barriers.Male pied flycatchers (Ficedula hypoleuca) and collared flycatchers (F. albicollis) differ in song and plumage traits. LÄS MER

  5. 29. Phylogeny and topological incongruence in the Rubioideae (Rubiaceae)

    Författare :Olle Thureborn; Catarina Rydin; Sylvain G. Razafimandimbison; Niklas Wikström; Michael D. Pirie; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Anthospermeae; cytonuclear discordance; gene trees; incomplete lineage sorting; incongruence; mitochondrial genome; nuclear genome; phylogenomics; phylogeny; plastid genome; Rubiaceae; Rubioideae; species trees; Plant Systematics; växtsystematik;

    Sammanfattning : The work with this thesis has focused on evolutionary relationships in the Rubioideae, the most species-rich subfamily of the large and diverse coffee family (Rubiaceae). Despite considerable efforts during the last decades, uncertainty regarding several relationships in this group has remained, either as a result of unconvincing statistic support, incongruent results, or insufficient taxon sampling. LÄS MER

  7. 30. Evolutionary history and chloroplast DNA variation in three plant genera: Betula, Corylus and Salix. : The impact of post-glacial colonisation and hybridisation

    Författare :Anna Palmé; Andrew Lowe; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Biology; chloroplast DNA; phylogeography; hybridization; phylogeny; Salix caprea; Betula pendula; Corylus avellana; Biologi; Biology; Biologi; naturvårdsbiologi; Conservation Biology;

    Sammanfattning : The great difference in the level of chloroplast variation and its geographic structure among the three main species studied here demonstrates that forest species do not form a homogeneous group. Hazel shows a genetic structure similar to many other thermophilous species and this structure, in combination with fossil evidence, indicates that the post-glacial colonisation of most of Europe originated in a refugium in western France while the Balkan and Italy were colonised from a south-eastern refugium. LÄS MER