The phylogeny of Schistidium (Bryophyta, Grimmiaceae) based on the primary and secondary structure of nuclear rDNA internal transcribed spacers

Abstract

The phylogeny of Schistidium (Bryophyta, Grimmiaceae) was studied on the basis of nucleotide sequences of internal transcribed spacers ITS1-2 of nuclear DNA and trnT-trnD region of chloroplast DNA. The consistency of phylogenetic trees constructed from nuclear and chloroplast sequences was shown. A basal grade and two large clades were resolved on the phylogenetic trees. Morphological characteristics specific for these clades were described. ITS1 and ITS2 secondary structures of Schistidium species were modeled using thermodynamic criteria. Four different structures of the longest ITS1 hairpin were identified. Possible paths of Schistidium evolution were considered based on the four types of ITS1 secondary structure and phylogenetic trees.