Molecular phylogeny of Shortia sensu lato (Diapensiaceae) based on multiple nuclear sequences

Molecular phylogenetics is commonly used to perform accurate taxonomic classification. Furthermore, nuclear multilocus sequences have been applied to resolve ambiguous phylogenetic relationships based on conventional markers such as chloroplast and nuclear ribosomal DNA. Here, we reconstructed the phylogenetic tree of Diapensiaceae to revise the traditional classification of the genus Shortia sensu lato (s.l.), which includes Shortia sensu stricto (s.s.) and Schizocodon; whether the latter taxon is treated as an independent genus or includes Shortia s.l. has been disputed since its first description. The phylogeny based on eight nuclear markers developed for this study indicated that Shortia s.l. is not a monophyletic group and that Schizocodon and Shortia s.s. are reciprocally monophyletic. In addition, Schizocodon would be sister to other genus Diapensia despite their morphological differentiation. Thus, our data suggest that Schizocodon represents an independent genus. Our study demonstrated that multiple nuclear loci can resolve obscure phylogenetic relationships determined using conventional markers.