Sökning: "ancestral sequences"

Visar resultat 6 - 10 av 29 avhandlingar innehållade orden ancestral sequences.

  1. 6. Autolytinae: molecules, morphology, and reproduction

    Författare :Arne Nygren; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Phylogeny; systematics; revision; new taxa; PhyloCode; reconstruction of ancestral states.;

    Sammanfattning : Autolytines constitute a well delineated group of syllid polychaetes, separated from other syllids by the presence of a sinuous pharynx, lack of ventral cirri and reproduction with dimorphic sexes. The group comprises c. 170 nominal species distributed worldwide, mostly inhabiting hard substrates restricted to the continental shelf. LÄS MER

  3. 7. Molecular phylogenetics and taxonomic issues in dragonfly systematics (Insecta: Odonata)

    Författare :Rasmus Hovmöller; Thomas Pape; Mari Källersjö; Kjell Arne Johanson; Karl Kjer; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Systematics and phylogenetics; Systematik och fylogeni;

    Sammanfattning : Dragonflies (Odonata) are one of the ancestral groups of extant insects. They represent one of the three most basal branches in the phylogeny of winged insects. The other two groups are the Ephemeroptera, mayflies, and Neoptera, the latter which covers the remaining winged insects. LÄS MER

  4. 8. Investigation of Mechanics of Mutation and Selection by Comparative Sequencing

    Författare :Michael C. Zody; Kerstin Lindblad-Toh; Leif Andersson; Chad Nusbaum; Henrik Kaessmann; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; chicken; chimpanzee; human; evolution; segmental duplication; structural variation; chromosomal rearrangement; comparative genomics; positive selection; selective sweep; Genetics; Genetik; Genetics; genetik;

    Sammanfattning : The process of evolution is of both scientific and medical interest. This thesis presents several studies using complete genomic reference sequences, comparative genomic data, and intraspecific diversity data to study the two key processes of evolution: mutation and selection. LÄS MER

  5. 9. Species Limits, and Evolutionary History of Glassfrogs

    Författare :Santiago Castroviejo-Fisher; Carles Vilà; Jennifer A. Leonard; Miguel Vences; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Amphibia; Anura; Biogeography; Centrolenidae; Diversification; Frogs; Molecular Phylogenetics; Neotropics; Pristimantis; Speciation; Species; Systematics; Taxonomy; Systematics and phylogenetics; Systematik och fylogeni; systematisk zoologi; Systematic Zoology;

    Sammanfattning : Recognizing the mechanisms of speciation and the limits of species is essential to understand the origin of biodiversity and how to conserve it. The general aims of my investigations during my doctoral studies were two-fold: to study evolutionary patterns and processes, and to provide specific and superspecific taxonomic classifications that try to reflect evolutionary history. LÄS MER

  7. 10. Genetic structure, demographic change and extinction dynamics in the collared lemming and woolly mammoth

    Författare :Eleftheria Palkopoulou; Love Dalén; Richard Edward Green; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Systematic Zoology; zoologisk systematik och evolutionsforskning;

    Sammanfattning : In light of current climate change it is critical to understand how different species have been affected in the past by well-known climatic events. In this thesis, DNA was retrieved from ancient material to study the population dynamics of two cold-adapted taxa that capture the extremes of body size range in mammals: the collared lemming (Dicrostonyx sp. LÄS MER