Allopolyploidy in Fragariinae (Rosaceae): comparing four DNA sequence regions, with comments on classification.

Potential events of allopolyploidy may be indicated by incongruences between separate phylogenies based on plastid and nuclear gene sequences. We sequenced two plastid regions and two nuclear ribosomal regions for 34 ingroup taxa in Fragariinae (Rosaceae), and six outgroup taxa. We found five well supported incongruences that might indicate allopolyploidy events. The incongruences involved Aphanes arvensis, Potentilla miyabei, Potentilla cuneata, Fragaria vesca/moschata, and the Drymocallis clade. We evaluated the strength of conflict and conclude that allopolyploidy may be hypothesised in the four first cases. Phylogenies were estimated using Bayesian inference and analyses were evaluated using convergence diagnostics. Taxonomic implications are discussed for genera such as Alchemilla, Sibbaldianthe, Chamaerhodos, Drymocallis and Fragaria, and for the monospecific Sibbaldiopsis and Potaninia that are nested inside other genera. Two orphan Potentilla species, P. miyabei and P. cuneata are placed in Fragariinae. However, due to unresolved topological incongruences they are not reclassified in any genus.