- Dpt. of Ecology and Genetics, Plant Ecology and Evolution, Uppsala University, Uppsala, Sweden
- Adaptation, Evolutionary Ecology, Hybridization / Introgression, Speciation
Potential adaptive divergence between subspecies and populations of snapdragon plants inferred from QST – FST comparisons
From populations to subspecies… to species? Contrasting patterns of local adaptation in closely-related taxa and their potential contribution to species divergence
Elevation gradients are convenient and widely used natural setups to study local adaptation, particularly in these times of rapid climate change [e.g. 1]. Marin and her collaborators  did not follow the mainstream, however. Instead of tackling adaptation to climate change, they used elevation gradients to address another crucial evolutionary question : could adaptation to altitude lead to ecological speciation, i.e. reproductive isolation between populations in spite of gene flow? More specifically, they examined how much local adaptation to environmental variation differed among closely-related, recently diverged subspecies. They studied several populations of two subspecies of snapdragon (Antirrhinum majus), with adjacent geographical distributions. Using common garden experiments and the classical, but still useful, QST-FST comparison, they demonstrate contrasting patterns of local adaptation to altitude between the two subspecies, with several traits under divergent selection in A. majus striatum but none in A. majus pseudomajus. These differences in local adaptation may contribute to species divergence, and open many stimulating questions on the underlying mechanisms, such as the identity of environmental drivers or contribution of reproductive isolation involving flower color polymorphism.
 Anderson, J. T., and Wadgymar, S. M. (2020). Climate change disrupts local adaptation and favours upslope migration. Ecology letters, 23(1), 181-192. doi: 10.1111/ele.13427
 Marin, S., Gibert, A., Archambeau, J., Bonhomme, V., Lascoste, M., and Pujol, B. (2020). Potential adaptive divergence between subspecies and populations of snapdragon plants inferred from QST – FST comparisons. Zenodo, 3628168, ver. 3 peer-reviewed and recommended by Peer Community in Evolutionary Biology. doi: 10.5281/zenodo.3628168
 Schluter, D. (2009). Evidence for ecological speciation and its alternative. Science, 323(5915), 737-741. doi: 10.1126/science.1160006