10/29/2022 0 Comments Calculate pi from polymorphism table![]() ![]() It is because of the fact that in case of reticulate evolution individual nrDNA copies are not homogenized immediately. Moreover, the region provides great potential to study historical or recent hybridization as well as introgression events. The nrDNA repeat units comprise DNA coding for RNA subunits and non-coding regions, which are widely applied in plant phylogenetics 9, 10, 11. In higher plants nrDNA is usually organized in long tandem repeats forming within the chromosomes the nucleolar organizing regions (NOR) 8. In our research, we focused on the repeat units of nuclear RNA genes (nrDNA). Thus, the aim of our paper was to find a molecular marker representing a sufficient level of informativeness to play a role of phylogenetic marker for Stipa. There is distinctly a lack of molecular method, that could explain both, molecular variability between selected taxa as well as phylogenetic relation within the genus Stipa. are separated from remaining Stipa species representing almost all distinguished sections within the genus 3, 4. However, in the light of existing researches using molecular method, only small group of Himalayan species comprised Stipa capillacea Keng, S. is currently the richest in species genus within Stipeae. With over 160 species (Nobis npbl.) native to Asia, Europe and north Africa, Stipa s. str., in which phylogenetic relationships remined unresolved 3, 4, 5. within Ptilagrostis Griseb, Piptatherum P.Beauv., Nasella, Achnatcherum and especially in Stipa s. Phylogenetic studies, based on cpDNA and ITS data have shown, that some of genera within Stipeae like, Jarava, Achnatherum, Piptochaetium, Austrostipa, Celtica F.M.Vazquez & Barkworth, Patis Ohwi, Hesperostipa (M.K.Elias) Barkworth, constituted well resolved and highly credible clades 1, 3, 4, 5, 6, 7. Currently, based on morphological and molecular data, the species belonging to the tribe were segregated into several genera 2, 3, 4, 5, with Stipa L., Nasella (Trin.) E.Desf., Achnatherum P.Beauv., Austrostipa S.W.L.Jacobs & Everett, Jarava Ruiz & Pav., Piptatherum P.Beauv. The tribe Stipeae comprised over 580 species, common or dominant in open grassland and steppes, with species diversity in temperate regions of Asia, Europe, Africa, Australia and America 1. However, the rate of evolution within the inter-repeats in the IGS region is extremely high and therefore it predestines the region for phylogenetic analyses of Stipa at genus level or in shallower taxonomic scale. Comparative analysis of nrDNA repeat units from Stipa to other representatives of Poaceae showed that their structure does not deviate from the general scheme. The region seems to be the most phylogenetically informative for Stipa from all the chloroplast and nuclear markers tested so far. Our results showed that the intergenic spacer region, and especially its part adjacent to 26 S nrDNA, is a molecular marker giving a real chance for a phylogeny reconstruction of Stipa. ![]() In the present study, we analyzed variability and phylogenetic informativeness of nuclear ribosomal DNA in six species from the genus against five other species from Poaceae including a division of this region into functional elements and domains. Researches made so far hadn’t delivered sufficient information about relationships between particular taxa from the genus of Stipa. The article takes up the problem of deficiency of molecular marker, which could illustrate molecular variability as well as phylogenetic relation within the genus of Stipa L. ![]()
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