Invasion patterns, genetic divergence, and barriers to dispersal
In a unique natural system we will be able to compare both the effect of physical dispersal limitation and the effects of a strong environmental selection within one and the same phylogenetic species. The dinoflagellate species Peridinium aciculiferum (freshwater) and Scrippsiella hangoei (marine) are genetically identical with regard to sequences of the rRNA gene (and therefore represent a single phylogenetic species), but differ in habitat choice, morphology, and salinity tolerance (and are therefore considered separate ecological species). We have identified three ecoptypes; one from freshwater lakes, one from the Baltic Sea, and one from saline lakes on Antarctica (Logares et al. 2007, Rengefors et al. 2008). A population genomic approach will be used to detect regions of selection and potential genes involved, in tandem with analyses of phenotypic variation of potential adaptive traits. This research has implications for the understanding of how free-living protists diverge and eventually speciate.
In a related project, financed by the Marine Microbial Eukaryote Transcriptome Project (Gordon and Betty Moore Foundation) we are using comparative transcriptome analyses to explore differences in three ecotypes of Peridinium aciculiferum (freshwater) and Scrippsiella hangoei (marine).
Funded by the Swedish Research Council VR.