A general assumption when addressing species whose distribution ranges span broad latitudinal gradients, is that northern populations are overall adapted to colder habitat conditions than southern populations.
The measured genetic distances among populations and the resulting structure of the network do not support a strong genetic divergence among the four populations examined in our study. One haplotype is even shared by PRA and SWE populations. However, our finding was based on neutral chloroplast DNA markers that are independent of selection and evolve at a slower rate than nuclear markers that are instead subject to gene flow. Similar results were obtained by Frajman et al. (2009) that detected very close relationships between V. alpina populations in southern and in northern Europe, as well in populations in Canada and Greenland in cpDNA markers (Frajman et al. 2009). Only a few nuclear markers showed divergence in that same study between two groups in Europe that appeared independent from latitude, but rather suggested independent dispersal events from glacial refugia, as for other alpine-artic species with disjunct distribution, like Ranunculus glacialis (Ronikier et al. 2012). In our study, similar genetic background in the four populations and the conservation of differences in growth rate among populations in our common garden experiment is also in agreement with local adaptation.