Sökning: "Species tree"

Visar resultat 1 - 5 av 313 avhandlingar innehållade orden Species tree.

  1. 1. Probabilistic Models for Species Tree Inference and Orthology Analysis

    Författare :Ikram Ullah; Jens Lagergren; Arndt von Haeseler; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; phylogenetics; phylogenomics; gene tree; species tree; expectation maximization; mixture model; dynamic programming; markov chain monte carlo; PrIME; JPrIME; Datalogi; Computer Science;

    Sammanfattning : A phylogenetic tree is used to model gene evolution and species evolution using molecular sequence data. For artifactual and biological reasons, a gene tree may differ from a species tree, a phenomenon known as gene tree-species tree incongruence. Assuming the presence of one or more evolutionary events, e.g. LÄS MER

  3. 2. Species Delimitation and Phylogenetic Relationships. A study of Silene sections Atocion and Cryptoneurae

    Författare :Zeynep Aydin; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Caryophyllaceae; Silene; Section Atocion; S. ertekinii; S. cryptoneura; S. aegyptiaca; SystematicsPhylogenetics; Species delimitation; Multispecies coalescent; Marginal likelihood; Species tree; DISSECT.;

    Sammanfattning : Abstract The existence of conflicting genealogies of different genes through the evolution of species complicates the inference of phylogenetic relationships. The Multispecies Coalescent (MSC) model provides a theoretical background that account for the stochasticity in the genealogical process, thus providing systematists with a potentially objective way of testing alternative hypotheses of putative species. LÄS MER

  4. 3. Climbing the Trichoptera Tree : Investigations of Branches and Leaves

    Författare :Tobias Malm; Kjell Arne Johanson; Wolfram Mey; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Trichoptera; Leptoceridae; Symphitoneuria; Gracilipsodes; Triplectides; morphology; DNA; systematics; phylogeny; New Caledonia; Madagascar; new species; new genus; Systematics and phylogenetics; Systematik och fylogeni; Systematic Zoology; zoologisk systematik och evolutionsforskning;

    Sammanfattning : The Trichoptera (caddisflies) is the largest of the primary aquatic insect orders, currently including more than 13,500 species. With more than 100 species new to science described annually, the known caddisfly diversity is rapidly increasing. In the first four papers of this Thesis, a total of 22 species new to science are described. LÄS MER

  5. 4. Species Limits and Systematics in Some Passerine Birds

    Författare :Per Alström; Timothy M. Crowe; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Organismic biology; Mirafra; Seicercus; Phylloscopus; Motacilla; species concepts; species limits; phylogeny; morphology; vocalisations; mitochondrial DNA; nuclear DNA; incongruence; Organismbiologi; Organism biology; Organismbiologi; systematisk zoologi; Systematic Zoology;

    Sammanfattning : I use morphological, vocal, molecular, behavioural, ecological and distributional data to re-evaluate the systematics of three passerine bird groups, the Mirafraassamica complex (bush-larks), the genus Seicercus ("spectacled-warblers"; with emphasis on the the S. burkii complex) and the genus Motacilla (wagtails). LÄS MER

  7. 5. Genetic variation in structured populations

    Författare :Marina Rafajlovic; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; genetic variation; varying population size; effective population size; mutation; recombination; migration; multiple paternity; geographic structure; tests of neutrality; gene tree; species tree;

    Sammanfattning : It is widely acknowledged that the process of speciation in the presence of gene flow between different ecotypes is common in nature. However, the mechanisms underlying speciation are not understood. LÄS MER