ITS1–5.8S rDNA–ITS2 sequence in 35S rRNA genes as marker for reconstruction of phylogeny of grasses (Poaceae family)

The problems associated with characteristics of the organization and evolution of the ITS1–5.8S rDNA–ITS2 region of 35S rRNA genes in the plant genome are discussed. It was demonstrated that phylogenetic hypotheses about the relationship of species and genera constructed based on the comparison of this region sequences in the nucleus genomes usually look quite plausible and are mainly consistent with the ideas of “classical” taxonomists about the relationships of species, although the traditional ideas about the borders of tribes and subtribes are not always phylogenetically confirmed. In general, the divergence of thousands copies of the ITS1 and ITS2 sequences present in the plant nucleus mainly correlated with the direction and rates of morphological divergence of taxa.