Wicke, Susann , Costa, Andrea , Muñoz, Jesús , Neinhuis, Christoph , Quandt, Dietmar .
From the exception to the rule: the re-arrangement(s) of the nuclear ribosomal DNA in land plants.
Until recently, it has been generally agreed that the nuclear ribosomal DNA (nrDNA) in land plants is uniformly organized in tandem arrays with up to several hundred copies. However, one element - the gene encoding the forth ribosomal RNA referred to as 5S rRNA - is located elsewhere forming a separate cluster. Yet, widely unnoticed, an alternative organisation of the nrDNA has been reported for a liverwort and a moss. In both cases, the 5S-rDNA has been found co-localized within the 45S repeat. In the present study, representatives of all major land plant lineages were investigated in more detail regarding a putative co-localization of the 45S/5S-rDNA. It can clearly be shown that the physical linkage of all nuclear ribosomal RNA genes is not unique to Marchantia and Funaria (Sone et al. 1999), but a common feature of land plants with multiple, apparently independent and rather unexpected 5S-transpositioning and duplication events. Phylogenetic implications and different transpositioning theories will be discussed based on circumstantial analyses of the structural organisation of the intergenic spacer regions of both co-localized and unlinked nrDNA. Furthermore, the incorporation of sequence data from whole genome sequencing projects allows to factor new aspects of nrDNA evolution in land plants.
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1 - University of Vienna, Institute of Botany, Department Plant Biogeography, Rennweg 14, Vienna, A-1030, Austria
2 - University of Bonn, Nees Institute for Biodiversity of Plants, Meckenheimer Allee 170, Bonn, D-53115, Germany
3 - Real Jardín Botánico (CSIC), Plaza de Murillo 2, Madrid, E-28014, Spain
4 - Technische Universitaet Dresden, Institut fuer Botanik, Zellescher Weg 20b, Dresden, D-01217, Germany
nuclear ribosomal DNA
5S ribosomal RNA
Presentation Type: Oral Paper:Papers for BSA Sections
Location: Cottonwood C/Snowbird Center
Date: Monday, July 27th, 2009
Time: 9:00 AM