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Evolutionary Processes and Spatial Genetic Variation in <i>Euphrasia stricta</i> on the Baltic Island of Gotland

<p>The identification of processes governing genetic structure at different spatial scales remains a major challenge in evolutionary biology and is of considerable applied interest in conservation biology. In <i>Euphrasia stricta</i> five varieties have been identified (<i>brevipila</i>, <i>gotlandica</i>, <i>stricta</i>, <i>suecica</i> and <i>tenuis</i>) based on differences in habitat, phenology and morphology. In this thesis, I examined genetic variation at AFLP and microsatellite marker loci in relation to variation in habitat and morphology within and among varieties of <i>E. stricta</i> on the island Gotland in the Baltic Sea. The results are discussed in relation to evolutionary processes acting within this species complex. </p><p>In a study conducted at the regional scale, the two early-flowering varieties <i>suecica</i> and <i>tenuis</i> each formed a genetically distinct group, while the three late-flowering varieties <i>brevipila</i>, <i>gotlandica</i> and <i>stricta</i> formed a third group. The results suggest that <i>suecica</i> and <i>tenuis</i> have ancient origins since they are genetically different both from the <i>brevipila</i>/<i>gotlandica</i>/<i>stricta</i> group and from each other despite their similar habitat preferences. This pattern was obtained using both marker systems. Discrepancies between AFLP and microsatellites were found in patterns of isolation by distance and in estimates of expected heterozygosity, <i>H</i><sub>e</sub>.</p><p>Focusing on the mixed genetic group <i>brevipila</i>/<i>gotlandica</i>/<i>stricta</i> and the causes behind their clustering together despite differences in morphology and habitat preferences, I performed a study at a smaller geographic scale. Studying a population of <i>E. stricta</i> I found that, although gene flow within the population was strong, it had not prevented the formation of genetic groups associated with micro-habitat properties. </p><p>An important result for conservation of the rare variety <i>suecica</i> is its distinct genetic separation from variety <i>tenuis</i>. If the aim of conservation is to preserve the uniqueness of <i>suecica,</i> the two varieties should be treated as separated entities. </p>

Identiferoai:union.ndltd.org:UPSALLA/oai:DiVA.org:uu-8536
Date January 2008
CreatorsKolseth, Anna-Karin
PublisherUppsala University, Department of Ecology and Evolution, Uppsala : Acta Universitatis Upsaliensis
Source SetsDiVA Archive at Upsalla University
LanguageEnglish
Detected LanguageEnglish
TypeDoctoral thesis, comprehensive summary, text
RelationDigital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, 1651-6214 ; 404

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