ИСТИНА

The study presents phylogenetic analysis of the genus Atraphaxis using nuclear ribosomal internal transcribed spacer ITS 1-2 nrDNA and trnL-F cpDNA sequence data. The clade Atraphaxis includes several species previously attributed to Polygonum L. s. str, on the basis of perianth morphology. Atraphaxis ovczinnikovii formerly treated as a member of Polygonum L. s.str. occupies sister position to the clade Atraphaxis based both on ITS 1-2 and trnL-F data, with the other species of Polygonum being nested in the clade Atraphaxis. Small number of informative nucleotide sites in ITS 1-2 and trnL-F region does not allow to receive fully resolved intrageneric relationships in the genus Atraphaxis. The clades or grades of the phylogenetic tree reconstructed on ITS 1-2 sequences do not correspond to three sections recognized on the basis of morphological characteristics, their representatives being intermingled within the clades. Despite of low support of subclades in ML-tree based on ITS 1-2 data, nucleotide polymorphism of some clones of an accession A. frutescens x A. pungens confirms its hybrid nature. Dual position of various accessions of the same taxon in ML tree based on ITS 1-2 data and analysis of nucleotide polymorphism of ITS 1-2 and trnL-F region let to suppose hybrid nature of A. virgata, A. replicata, A. decipiens, A. compacta, A. karataviensis. Various morphological species have from one to five variants of trnL-F sequences, some variants of trnL-F region are common for a group of species. The ITS 1-2 and trnL-F regions of A. ovczinnikovii, A. ariana and A. badghysi differ by the highest number of nucleotide replacements and seem to be the most ancient species in the group. Nucleotide polymorphism of ITS 1-2 clones of A. tortuosa grouping with different species is probably the result of incomplete outsorting of lineages. Morphological differentiaton of majority species is ahead of molecular differentiation.