Abstract: The genus Luzula consists of 115 species distributed throughout the world. Luzula is monophyletic, but
species relationships within the genus are difficult to determine primarily due to the similar morphology
even within geographically remote taxa (especially within the section Luzula). The plastome trnL intron,
trnL-F intergenic spacer and the nuclear ribosomal ITS1-5.8S-ITS2 regions were analysed using maximum
parsimony and maximum likelihood reconstruction in 93 species of Luzula. The incongruent phylogenetic
signals obtained from the chloroplast and the nuclear genomes point to incomplete lineage sorting as
well as recent hybridisation in this group. Although tree-building analyses revealed several well-supported
lineages, the outcomes for many groups were ambiguous. In the total evidence tree, Luzula species
were grouped within six main clades (1. subgenus Marlenia, 2. subgenus Pterodes except for L. pilosa, 3.
sections Anthelaea and Nodulosae, 4. sections Diprophyllatae and Thyrsanochlamydeae, 5. section Alpinae
except for a few species and 6. section Luzula). The subgenus Marlenia occupies the early derived lineage
within the genus Luzula. The traditionally accepted subgenera Pterodes and Luzula (and its sections)
appear to be non-monophyletic. A statistical parsimony network approach showed that ancient haplotypes
and ribotypes co-occur with their descendants in Luzula. Furthermore, many haplotypes are shared
among different species. Within the Luzula section Luzula, both recent hybridisation and incomplete lineage
sorting of ancestral polymorphisms may represent potential sources of the incongruence between
chloroplast and nuclear data.
Abstract: Nuclear sequences of ITS1-5.8S-ITS2 region of rDNA may be an important source of phylogenetically informative data provided that nrDNA is cloned and the character of sequence variation of clones is properly analysed. nrDNA of selected Taraxacum sections was studied to show sequence variation differences among diploid sexual, tetraploid sexual and polyploidy agamospermous species. We examined nucleotide characteristics, substitution pattern, secondary structure, and the phylogenetic utility of ITS1-5.8S-ITS2 from 301 clones of 32 species representing 11 sections. The most divergent sequences of ITS1&2 differed by 17.1 % and in 5.8S only by 3.7 %. The ITS1-5.8S-ITS2 characteristics, integrity and also stability of secondary structures confirmed that pseudogenes are not responsible for the above variation. The within-individual polymorphism of clones implies that the concerted evolution of ITS cistron of agamospermous polyploid Taraxacum is remarkably suppressed. Sequences of ITS clones proved to be a useful tool for mapping pathways of complex reticulation (polyploid hybridity) in agamospermous Taraxacum.
Abstract: A phylogenetic analysis of the Juncaceae was conducted to assess relationships within the genera Juncus, Luzula and five other small South American genera (Distichia, Marsippospermum, Oxychloë, Patosia and Rostkovia). We examined parallel datasets from organelles (mtDNA: atp1 gene, cpDNA: trnL intron, trnL-F intergenic spacer, rbcL gene) with respect to qualities relevant to the phylogenetic analysis of the Juncaceae. The main aim of our work was to produce a robust phylogeny of the Juncaceae validated by data from both organelles. Our data confirm the monophyly of the genus Luzula, but do not provide support for monophyly of the genus Juncus. The majority of taxa clustered within two subgenera, Agathryon and Juncus, morphologically supported by the presence or absence of bracteoles and cymose or racemose inflorescences respectively. The subgenus Juncus is divided into two separate clades, the first closely related to the subgenus Agathryon and the second in the most basal part of the tree. Moreover, small South American genera clustered together with Juncus sect. Graminifolii and also with Juncus sect. Juncus. In fact, comparison of results from separate analyses of mitochondrial and plastome genes demonstrates that the general resolution of main topology of the atp1 tree is similar to the separate rbcL tree; the genus Juncus is better resolved, but the genus Luzula remains mainly polytomic.
Notes: Drábková L., Kirschner J., VlÄek Ä. (2002) Historical herbarium specimens in molecular taxonomy of the Juncaceae: A comparison of DNA extraction and amplification protocols. Plant Molecular Biology Reporter Vol.20/2, 161-175.
Drábková L., Kirschner J., Seberg O., Petersen G., VlÄek Ä. (2003) Phylogeny of the Juncaceae based on rbcL sequences, with special emphasis on Luzula DC. and Juncus L. Plant Syst. Evol. 240, 133-147.
Drábková L., Kirschner J., VlÄek Ä., PaÄes V. (2004) TrnL-trnF intergenic spacer and trnL intron define clades within Luzula and Juncus (Juncaceae). J. Mol. Evol. 59(1), 1-10.
Drábková L., Kirschner J., (2004): Juncus uruguensis Griseb. - a member of section Juncotypus (Juncaceae, subg. Agathryon).- Nord. J. Bot. 22(6): 687-691.
Drábková L., Kirschner J., VlÄek Ä. (2006). Phylogenetic relationships within Luzula DC. and Juncus L. (Juncaceae): A comparison of phylogenetic signals of trnL-trnF intergenic spacer, trnL intron and rbcL plastome sequence data. Cladistics 22/2, 132-143.
Drábková L., VlÄek Ä. (2007) The phylogenetic position of Oxychloë (Juncaceae): evidence from one nuclear, three plastid regions and morphology. Taxon 56/1, 95-102.
Kristiansen K., Cilieborg M., Drábková L., Jørgensen T., Petersen G., Seberg O. (2004) DNA taxonomy â the riddle of Oxychloë. Syst. Bot. 30(2), 284-289.
