Sökning: "purifying selection"

Visar resultat 1 - 5 av 16 avhandlingar innehållade orden purifying selection.

1. 1. Evidence for adaptive variation at the genes coding for cytosolic phosphoglucose isomerase (PGIC) in Festuca ovina L

   Författare :Yuan Li; Biodiversitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; 3-D protein structure; purifying selection; positive selection; cDNA sequences; local adaptation; alvar grasslands; Festuca ovina; Phosphoglucose isomerase; PgiC loci; SNPs; nucleotide polymorphism; horizontal gene transfer;

   Sammanfattning : The gene (Pgi) encoding the enzyme phosphoglucose isomerase (PGI) which plays a central role in the main pathways of carbon metabolism has been shown to be of adaptive significance in a wide range of different species. Earlier studies of enzyme electromorph variation in the grass Festuca ovina suggest that variation in cytosolic PGI (PGIC) may be involved in the adaptive response of F. LÄS MER

3. 2. Population genomic analyses of regulatory variation and selection in Brassicaceae species

   Författare :Robert Horvath; Tanja Slotte; Peter Hambäck; Douglas G. Scofield; Matthew Webster; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Capsella grandiflora; Arabidopsis thaliana; Arabidopsis lyrata; natural selection; gene expression variation; DNA and gene body methylation; transposable elements; DNA accessibility; gene expression noise; epigenetic silencing; linked selection; ekologi och evolution; Ecology and Evolution;

   Sammanfattning : The impact of selection on regulatory variation and the contribution of regulatory changes to phenotypic variation has long been debated in evolutionary genetics. Because cis-regulatory elements such as promoters and enhancers can be difficult to identify, it has been more challenging to quantify the impact of selection on variation in cis-regulatory regions than in protein-coding regions. LÄS MER

4. 3. Cis-regulatory variation and divergence in Capsella

   Författare :Kim A. Steige; Tanja Slotte; Jeff J. Doyle; Uppsala universitet; []
   Nyckelord :Capsella; Shepherd s Purse; cis-regulatory changes; allele-specific expression; mating system shift; floral evolution; polyploidy; positive selection; purifying selection; transposable elements; small RNA; methylation; transposable element silencing; distribution of fitness effects;

   Sammanfattning : Cis-regulatory changes in e.g. promoters or enhancers that affect the expression of a linked focal gene have long been thought to be important for adaptation. In this thesis, I investigate the selective importance and genomic correlates of cis-regulatory variation and divergence in the genus Capsella, using massively parallel sequencing data. LÄS MER

5. 4. Genomic studies of mating system variation in flowering plants

   Författare :Juanita Gutiérrez-Valencia; Tanja Slotte; Magne Friberg; Mario Vallejo-Marín; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; mating system evolution; cross- and self-fertilization; distyly; supergenes; complex phenotypic polymorphism; convergent evolution; homostyly; loss-of-function mutation; intrasexual competition; pollen; purifying selection; Linum; Arabis alpina; Ecology and Evolution; ekologi och evolution;

   Sammanfattning : The striking diversity of reproductive strategies that flowering plants exhibit remains one of the most intriguing conundrums in evolutionary biology. Pollination-related traits and mating system strategies have a major impact on the processes shaping plant evolution through their effects on genetic diversity and selection. LÄS MER

7. 5. The roles of demography and natural selection in shaping genome-wide variation of Norway spruce

   Författare :Xi Wang; Pär K. Ingvarsson; Carolina Bernhardsson; Xiao-Ru Wang; Nathaniel Street; Tanja Pyhäjärvi; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Norway spruce; whole-genome resequencing; variant calling; genetic linkage map; nucleotide diversity; natural selection;

   Sammanfattning : Understanding the relative contribution of genetic drift, natural selection, and mutation to genetic variation, and quantifying adaptive evolution and the effects of natural selection in species are enduring goals of evolutionary genetics. Norway spruce (Picea abies) is one of the most important conifer species that dominates from both an ecological and economical point of view in many boreal ecosystems. LÄS MER