[Phylogenetic relationships of Oxytropis chankaensis Jurtz. and Oxytropis oxyphylla (Pall.) DC. (Fabaceae) inferred from the data of sequencing of the ITS region of the nuclear ribosomal DNA operon and intergenic spacers of the chloroplast genome].

The autotetraploid Oxytropis chankaensis Jurtz. is the only representative of the section Baicalia (subgenus Oxytropis, Fabaceae) in Primorskii Krai, and its range is restricted to the sandy belt along the western coast of the Khanka Lake. The type species of the section Baicalia is O. oxyphylla (Pall.) DC., and O. chankaensis is regarded by some authors as its synonym. Analysis of the ITS sequences showed that O. chankaensis is phylogenetically closely related to the species O. oxyphylla and O. racemosa Turcz. from the section Baicalia and also to the species O. anertii Nakai., O. ciliata Turcz., and O. inschanica H. C. Fu & S. H. Cheng from the section Xerobia, but this analysis failed to resolve the phylogenetic relationships of the species within the genus Oxytropis. The analysis of the trnH-psbA, trnL-trnF, trnS-trnG, and petG-trnP regions of cpDNA revealed molecular differences between O. chankaensis and O. oxyphylla that are indicative of considerable divergence of their chloroplast genomes. The ancestral lineages of these species diverged nearly 2 million years ago, which confirms the taxonomic validity of O. chankaensis. Taking into account the ecological specificity of O. chankaensis and the present-day distribution range of O. oxyphylla, it can be assumed that they descended from one ancestral maternal lineage that gave rise to the species of the section Baicalia.