Inference of reticulation in outcrossing allopolyploid taxa: caveats, likelihood and perspectives

Single- or low-copy nuclear sequences are now widely employed for phylogenetic reconstruction. In a new paper, Ferguson and Sang apply this approach to allotetraploid species of peonies Paeonia and document the first case of natural homoploid hybrid speciation between tetraploid taxa. This surprising finding could shed light on the relationship between the two main pathways of hybrid speciation: allopolyploidization and homoploid hybrid speciation. In addition, this work illustrates both the promise and uncertainty associated with the reconstruction of reticulate phylogenies using molecular tools.