My main research interests are within plant evolution and systematics and have so far concentrated on polyploid molecular systematics and taxonomy of arctic-alpine vascular plants.
My research group concentrate on diverse aspects of polyploid and reticulate evolution with strong links to the Arctic, which is one of the most polyploid-rich areas on Earth. The Arctic flora consists of numerous recently evolved polyploids. Polyploidization has probably occurred repeatedly through the entire Quaternary. Successive hybridization and polyploidization events can build up high-ploid species complexes of allopolyploids with network-like histories. One such example is the Cerastium alpinum complex where high ploidy levels dominate and no diploid progenitors are known. Using non-coding sequences of low-copy number genes, we are untangling the history of complex genome mergings in this species complex. Polyploidy is often accompanied by a loss of or change in normal sexual reproduction. One of the classical views of polyploid plants is that they have higher rates of self-fertilization than their diploid progenitors and that polyploidy may provide a buffer towards the effects of inbreeding. Plants have evolved several mechanisms to avoid self-fertilization; one of these is the self-incompatibility system, which is a genetically controlled pollen-pistil recognition system that provides a barrier to self-fertilization. My research group is involved in a project where we look at the effect of polyploidy on the self-incompatibility system in the Arabidopsis lyrata/petraea complex. Although previously considered a mechanism leading to ‘evolutionary dead ends’, polyploidy is now acknowledged as an important process in plant evolution, whereas the general perception is still that polyploidy is too rare to be a significant factor in animal evolution. However, polyploidy occurs in a wide range of animal groups, and there is an urgent need to screen for polyploidy in both plants and animals to combine results from both groups to understand the factors involved in the origin and establishment of polyploid lineages, as well as the genetic and ecological consequences of genome duplication. In close cooperation with other CEES core-members and international collaborators our intentions are in the near future to include both terrestrial plants and a range of animals in a multidisciplinary effort to better understand the adaptive value of and evolutionary consequences of polyploidy.
In collaboration with mycologists at the Department of Biology, I am also involved in a project where we will 1) analyse population structure and phylogeographic pattern in two mycorrhiza-forming plant species, 2) determine the diversity of fungal root symbionts associated with the two model plants, and 3) perform a comparative phylogeographic analysis of a host plant and its fungal root symbionts in order to see whether they have co-migrated and colonized the North Atlantic region jointly.