Genetic structure at different spatial scales in metapopulations of Silene tatarica
1University of Oulu, Faculty of Science, Department of Biology
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|Persistent link:|| http://urn.fi/urn:isbn:9514277694
|Publish Date:|| 2005-08-16
|Thesis type:||Doctoral Dissertation
|Defence Note:||Academic Dissertation to be presented with the assent of the Faculty of Science, University of Oulu, for public discussion in Kuusamonsali (Auditorium YB210), Linnanmaa, on August 26th, 2005, at 12 noon
Docent Anni Harju
Docent Anna Westerberg
The genetic structure at different spatial scales and growing habitats was studied on Silene tatarica, using AFLP and microsatellite markers. S. tatarica is a rare perennial plant occurring along riverbanks and shores of two annually flooding rivers in Finland. Regional scale analysis based on AFLP fragment analysis showed that at Oulanka River population structure represented mostly classical metapopulation model. In general, colonization-extinction processes had an important role, dispersal between subpopulations was limited and genetic differentiation was independent of geographic location.
The same subpopulations were partly used to study spatial genetic structuring within subpopulations. Spatial autocorrelation revealed clear spatial genetic structure in each subpopulation. Paternity analysis in an isolated subpopulation showed small amounts of inbreeding, restricted seed dispersal and pollen flow through the subpopulation. Factors affecting the creation and maintenance of spatial genetic structure within subpopulation were most likely colonization events and restricted seed dispersal.
The impact of river regulation on the genetic structure of populations was studied by comparing results from Oulanka River to the results obtained from second main growing area, Kitinen River. Oulanka River is a natural river system, whereas Kitinen is a regulated river. The overall regional scale studies did not indicate major differences between river systems. There were some clear population genetic differences between rivers but there were no clear evidence that those would have been caused by river regulation. More likely differences were related to the marginal location of Kitinen population at the edge of the distribution range. Studies indicated that regardless of the species rarity in Finland, active management measures are not currently needed in either S. tatarica growing area.
Species specific microsatellite loci were isolated to complement AFLP studies. During the microsatellite isolation, an interesting amplification pattern was detected and studied further. It was suggested that there were repetitive areas within genome containing microsatellites resulting in unusual amplification. The most likely explanation for this phenomenon would be transposable elements containing proto-microsatellite areas. The microsatellites isolated could have evolved mostly from those proto-microsatellites.
Acta Universitatis Ouluensis. A, Scientiae rerum naturalium
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