Molecular and Cytogenetic Analysis of rDNA Evolution in Crepis Sensu Lato |
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Authors: | Magdalena Senderowicz Teresa Nowak Hanna Weiss-Schneeweiss Laszlo Papp Bozena Kolano |
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Affiliation: | 1.Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia in Katowice, 40-007 Katowice, Poland; (M.S.); (T.N.);2.Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, A-1030 Vienna, Austria;3.Eötvös Loránd University Botanical Garden, Illés u. 25, 1083 Budapest, Hungary; |
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Abstract: | Although Crepis was the first model plant group in which chromosomal changes were considered to play an important role in speciation, their chromosome structure and evolution have been barely investigated using molecular cytogenetic methods. The aim of the study was to provide a better understanding of the patterns and directions of Crepis chromosome evolution, using comparative analyses of rDNA loci number and localisation. The chromosome base number and chromosomal organisation of 5S and 35S rDNA loci were analysed in the phylogenetic background for 39 species of Crepis, which represent the evolutionary lineages of Crepis sensu stricto and Lagoseris, including Lapsana communis. The phylogenetic relationships among all the species were inferred from nrITS and newly obtained 5S rDNA NTS sequences. Despite high variations in rDNA loci chromosomal organisation, most species had a chromosome with both rDNA loci within the same (usually short) chromosomal arm. The comparative analyses revealed several independent rDNA loci number gains and loci repositioning that accompanied diversification and speciation in Crepis. Some of the changes in rDNA loci patterns were reconstructed for the same evolutionary lineages as descending dysploidy. |
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Keywords: | rDNA loci Crepis 5S rDNA NTS nrITS chromosomes FISH phylogeny |
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