Sökning: "local genetic variation"

Visar resultat 16 - 20 av 108 avhandlingar innehållade orden local genetic variation.

1. 16. Population differentiation in Lythrum salicaria along a latitudinal gradient

   Författare :Katarina Olsson; Jon Ågren; Susan Kalisz; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; additive genetic variance; clinal variation; evolutionary constraints; G matrix; genetic correlation; natural selection; pollen limitation; population differentiation; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi; ekologisk botanik; Ecological Botany;

   Sammanfattning : In this thesis, quantitative genetic approaches, common-garden experiments, and field studies were combined to examine patterns of population differentiation and the genetic architecture of characters of putative adaptive significance in the widely distributed perennial herb Lythrum salicaria. In this work, I (1) documented patterns of population differentiation in phenology, life-history, and morphology along latitudinal gradients at different geographical scales, (2) investigated the genetic architecture of phenology, flower morphology, and inflorescence size, and (3) combined estimates of phenotypic selection in the field with information on the genetic variance-covariance matrix (G) to examine potential constraints to adaptive evolution. LÄS MER

3. 17. Intraspecific variation in Rhinanthus angustifolius. Local adaptation, phenotypic plasticity and geographical structure

   Författare :Anneli Jonstrup; Biodiversitet; []
   Nyckelord :Ecotype; Local adaptation; Phenotypic plasticity; Parallel evolution; Geographical structure; Hemiparasite; Rhinanthus;

   Sammanfattning : Plant species often adapt to local environmental conditions, which can result in the formation of genetically and phenotypically distinct ecotypes. Ecotypes can evolve rapidly, and may be a first step in the process of ecological speciation. LÄS MER

4. 18. Effects of Agriculture on Abundance, Genetic Diversity and Fitness in the Common Frog, Rana temporaria

   Författare :Markus Johansson; Anssi Laurila; Juha Merilä; Craig R. Primmer; Michael W. Bruford; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Biology; agriculture; agrochemicals; amphibians; effective population size; genetic diversity; genetic structure; hierarchical sampling; microsatellites; Rana temporaria; Biologi; Biology; Biologi;

   Sammanfattning : The aims of this thesis were to evaluate the effects of agriculture on amphibians in terms of (i) population genetic consequences of agriculture-induced spatial changes of the landscape and (ii) local adaptation and tolerance to frequently used agrochemicals. The study was performed using the common frog Rana temporaria as a model. LÄS MER

5. 19. Geographic Variation, Hybridization and Evolution in the Bladder Campions, Silene vulgaris and S. uniflora (Caryophyllaceae)

   Författare :Eva Månsby; Biologiska institutionen; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; chemotaxonomy. Physiology of nonvascular plants; Systematisk botanik; Växtgenetik; Systematic botany; taxonomy; morphology; phytogeography; Plant genetics; Paternal effects; Seed polymorphism; Ecology; Ekologi; Crossing barriers; cpDNA markers; Genetic variation; Hybridization; Post-glacial migration; Allozymes; Silene vulgaris; Silene uniflora; taxonomi; morfologi; kemotaxonomi. Växters fysiologi inte kärlväxter .;

   Sammanfattning : In the present thesis, I investigated the inter- and intraspecific variation in the Silene vulgaris/uniflora species-complex (the bladder campions). I have focused on the effects of past and present hybridization both on a large scale ? over the whole of Europe ? and on a local scale. Silene vulgaris and S. LÄS MER

7. 20. Understanding the genetic basis of complex traits

   Författare :Yanjun Zan; Örjan Carlborg; Pär Ingvarsson; Uppsala universitet; []
   Nyckelord :genetic architecture; complex traits; epistasis; multi-allelic; genotype by environment interaction; polygenic adaptation; Biology with specialization in Evolutionary Genetics; Biologi med inriktning mot evolutionär genetik;

   Sammanfattning : Recent advances in genetics and genomics have provided numerous opportunities to study the genetic basis of complex traits. Nevertheless, dissecting the genetic basis of complex traits is still challenged by the complex genetic architecture, in which many genes are involved, and many have small contributions to phenotypic variation, interactions with other genes or environmental factors. LÄS MER