Phylogenetic relationships and the identification of allopolyploidy in circumpolar Silene sect. Physolychnis

Species complexes are groups of closely related species with ambiguous delimitation, often composed of recently diverged lineages. Polyploidization and uniparental reproduction (i.e., selfing and apomixis) can play important roles in the origin of species complexes. These complexes pose challenges for species-based scientific questions, such as the estimation of species richness or conservation prioritization.

We determined the potential of resolving taxonomically complex groups using target enrichment in the circumpolar Silene uralensis complex (Caryophyllaceae). We proposed a metric using genetic distances between phased alleles to distinguish diploids from allopolyploids.

Our results identified geographic structure of populations, with the northern American and Greenlandic samples having a common ancestor. We found little phylogenetic support for the most recent taxonomic treatment of the Silene uralensis complex.

The study highlights the use of target enrichment in testing taxonomic hypotheses in diploids and the challenges of studying recently diverged lineages.