Sökning: "deleterious mutations"

Visar resultat 1 - 5 av 35 avhandlingar innehållade orden deleterious mutations.

  1. 1. Experimental Evolution : and Fitness Effects of Mutations

    Författare :Anna Knöppel; Dan I Andersson; Stanley Maloy; Uppsala universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Experimental evolution; Fitness effects; mutations; S20; fis; ribosome; horizontal gene transfer; adaptation; synonymous mutations; Mikrobiologi; Microbiology;

    Sammanfattning : Bacteria have small, streamlined genomes and evolve rapidly. Their large population sizes allow selection to be the main driver of evolution. With advances in sequencing technologies and precise methods for genetic engineering, many bacteria are excellent models for studying elementary questions in evolutionary biology. LÄS MER

  2. 2. On the evolutionary effects of linkage and deleterious mutations in small populations

    Författare :Snæbjörn Pálsson; Uppsala universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Developmental biology; Breeding systems; Daphnia pulex; deleterious mutations; linkage; neutral variation; Utvecklingsbiologi; Developmental biology; Utvecklingsbiologi; Genetics; genetik;

    Sammanfattning : The aim of this thesis is to evaluate the effect of deleterious mutations and linkage on variation in neutral markers and fitness in small populations. The study is based on two main approaches, one by using computer simulations, the other by exploring genetic variation in a cyclical parthenogen, Daphnia pulex (Crustacea: Cladocera). LÄS MER

  3. 3. Surviving the ratchet : Modelling deleterious mutations in asexual populations

    Författare :Jonas Söderberg; Otto Berg; Laurence Loewe; Uppsala universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; Theoretical biology; Population genetics; Stochastic modelling; Genome evolution; Muller s Ratchet; Genetics; Genetik; Organism biology; Organismbiologi; Biology; Biologi; Biologi med inriktning mot molekylär evolution; Biology with specialization in Molecular Evolution;

    Sammanfattning : One of the most unforgiving processes in nature is that of Muller's ratchet, a seemingly irreversible accumulation of deleterious mutations that all organisms have to deal with or face extinction. The most obvious way to avoid fitness collapse is recombination, though asexual populations usually do not have the luxury of recombining freely. LÄS MER

  4. 4. Mechanisms of adaptive mutations in bacteria

    Författare :Elisabeth Kugelberg; Karolinska Institutet; Karolinska Institutet; []
    Nyckelord :MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP;

    Sammanfattning : Bacteria have the ability to adapt to various challenging environments. The rate, extent and consequences of bacterial adaptation depend on both microbial and environmental factors. LÄS MER

  5. 5. Mechanisms of adaptation to the fitness cost of antibiotic resistance

    Författare :Wilhelm Paulander; Karolinska Institutet; Karolinska Institutet; []
    Nyckelord :MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP;

    Sammanfattning : The dissemination and persistence of antibiotic resistance, is not only depending on the volume of drugs used but also on the resistance mechanisms effect of bacterial fitness (reproductive ability). Fitness is a multifactorial parameter that is comprised of the relative growth rate of the resistant pathogen in the host and in the environment, as well as the clearance and transmission rates compared to susceptible strains. LÄS MER