The overall coherence in my research activities is a strong-willed wish to contribute to a deeper understanding of plant evolution and speciation.
From the start, one focus has been polyploid evolution. As polyploid plants are found at high numbers in arctic and alpine regions, this fitted well with a general focus on phylogeny and phylogeography of the arctic-alpine flora. Polyploidization has probably occurred repeatedly through the entire Quaternary. Successive hybridization and polyploidization events have build up high-polyploid species complexes of allopolyploids with network-like histories.
Important in the speciation process is the establishment of reproductive barriers. In the NFR funded MOLBAR project (The molecular basis of postzygotic hybridization barriers in plants), we study postzygotic barriers that prevent the embryo from developing normally when germ cells from two different species merge. The embryo develops inside the seed, and in most plants the seed contains in addition nutritive tissue (endosperm) that the new plant needs to grow big. We specifically study the embryo and endosperm development in seeds resulting from crosses between different Brassicaceae species.
Species are the most fundamental unit in nature, and yet we know little about how long it takes for new species to arise and what factors influence the rate of speciation. In the SpeciationClock project (How fast does the "speciation clock" tick in selfing versus outcrossing lineages?), we address the fundamental question of how fast new species arise, and specifically test if the plant ‘speciation clock’ ticks faster in self-fertilizing than outcrossing lineages. Our main objective is to develop and empirically test theoretical models of the impact of mating systems on the genetic architecture and rate of speciation, i.e. the ticking of the ‘speciation clock(s)’.