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 contains hitherto undetected cryptic species diversity (Gustafsson et al. 2014, Skrede et al. 2008, Grundt et al. 2006).
In this project, we will perform whole genome sequencing and characterize the genetic architecture of postzygotic reproductive isolation in two Arctic plant species that have previously been shown to harbor cryptic species: Draba nivalis and Cochlearia groenlandica.
Moving beyond the Arctic, we aim to test whether more southern floras contain similarly high, but previously undetected, cryptic biological species diversity. In particular, using crossing experiments and high-throughput sequencing we will address whether plant species that predominantly self-fertilize contain more cryptic species than those that predominantly outcross when controlled for lineage age.
The project will provide new and potentially groundbreaking insights into both the dynamics of the latitudinal diversity gradient and the fundamental process of species divergence in its earliest stages. 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 SpArc project is funded by a research grant from the Research Council of Norway.
References
Gustafsson ALS, Skrede I, Rowe HC, Gussarova G, Borgen L, Rieseberg LH, Brochmann C, Parisod C (2014) Genetics of Cryptic Speciation within an Arctic Mustard, Draba nivalis. PLoS ONE 9(4): e93834. doi:10.1371/journal.pone.0093834
Skrede I, Brochmann C, Borgen L, Rieseberg LH (2008): Genetics of intrinsic postzygotic isolation in a circumpolar plant species, Draba nivalis (Brassicaceae). Evolution 62:1840–1851.
Grundt HH, Kjolner S, Borgen L, Rieseberg LH, Brochmann C (2006): High biological species diversity in the arctic flora. Proceedings of the National Academy of Sciences of the United States of America 103: 972–975.
