Q36618590
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DNA barcoding is a technique of species identification by using standardized DNA sequence. This technique represents a challenge in the taxonomic approaches avoiding the need of exact knowledge of morphology, particularly when diagnostic morphological features are absent. There has been a considerable debate regarding a locus choice for standard barcode of land plants. Two-locus plastome sequences have been recommended by Plant working group of CBOL for plant barcode: rbcL and matK. The future purposes of this technique suggest using it instead of simple replacement of morphological data to identification of newly found species, recognizing species boundaries and cryptic species, or determination illegally obtained organisms and material even in cases where diagnostic features have been artificially modified.
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.
- MeSH
- DNA chloroplastová genetika MeSH
- DNA rostlinná genetika MeSH
- fylogeneze MeSH
- Magnoliopsida klasifikace genetika MeSH
- polymerázová řetězová reakce MeSH
- pravděpodobnostní funkce MeSH
- ribozomální DNA genetika MeSH
- sekvenční analýza DNA MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
