Abstract
Decreasing species diversity from low to high latitudes is a major pattern in ecology, but the extent to which this pattern depends on morphologically rather than biologically defined species is unclear. We have recently shown that the supposedly species-poor Arctic flora displays exceptionally high rates of formation of cryptic biological (i.e., reproductively isolated) species, possibly associated with a selfing mating system and based on multiple genetic mechanisms. In this project, we will identify the genomic mechanisms of postzygotic reproductive isolation in two Arctic systems, and test whether more southern floras contain similarly high, but hitherto undetected, cryptic biological species diversity. In particular, based on crossing experiments and high-throughput sequencing we will address whether selfers contain more cryptic species than outcrossers when controlled for lineage age, and whether polyploid formation from a diverse pool of recently diverged, cryptic diploid species can help explain why the Arctic harbours one of the most polyploid-rich floras on Earth. The project will provide new and potentially ground-breaking insights into both the dynamics of the latitudinal diversity gradient and the fundamental process of species divergence. Furthermore, the results will facilitate a re-evaluation of how conservation assessments and evolutionary studies are impacted by the widespread use of non-biological species concepts. The international project team will consist of one postdoc and one technician funded by RCN and one postdoc funded by NHM Oslo, in addition to leading experts on speciation genetics, mating system evolution, polyploid speciation, genome sequencing, bioinformatics, flow cytometry, experimental plant culturing and crossing, morphometrics and plant systematics.
Norway