Select output fields
|Family||Genus||Specific epithet||Specific authority||Infraspecific epithet||Infraspecific authority|
|2C mean1(pg)||2C mean1(mbp)||2C range1 pg||Life cycle|
|Other specifications (cultivar, population, strain, etc.)||Original reference||Journal||Year|
|Telomere type||Telomere type based in||genome sequenced||hybrid|
|Number of 5S signals||Range of 5S signals||Position2 of 5S signals (5S P)|
|Number of 35S3 signals||Range of 35S signals||Position2 of 35S signals (35S P)||Arrangement|
|Total number of rDNA signals (5S+35S) (Total)||Number of chromosomes with both 5S and 35S signals (SC)|
|Number of chromosomes with both 5S and 35S in the same arm (SA)||Number of chromosomes with co-localized 5S and 35S signals (Coloc.)|
|Family Genus Specific epithet|
|Chromosome number from: - Ploidy level from: -|
Land plants group
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1 1C genome size and n chromosome number for bryophytes.
2 Position refers to that of most chromosomes in the species and can be either interstitial (i), (peri-)centromeric (c) and (sub-)terminal or satellite (t).
3 35S=45S=18S-5.8S-26S rDNA
The Plant rDNA database is an online resource providing information on numbers and positions of ribosomal DNA signals and their structures for 2148 plant species (3783 entries). The data have been obtained from 785 publications on plant molecular cytogenetics using mostly fluorescent in situ hybridisation (FISH) of the 5S and the 18S-5.8S-26S ribosomal RNA genes (rDNA). Where available it also includes information on ploidy level, chromosome number, genome size and life cycle. This release newly includes information on telomere composition and on plant genomes sequenced.
Number, position and structure of the 5S and 18S-5.8S-26S rDNA clusters in chromosomes can be characteristic of a given species or genus and used for comparative purposes, including studies in crop science, plant breeding, evolutionary biology, systematics, etc. Telomere sequences have also been used to characterize plant karyotypes.
The database holds rDNA loci information adn telomere composition on angiosperms, gymnosperms, bryophytes and pteridophytes from papers already published or in press up to December 2016. Regular updates are planned.
Database content in Release 3.0. Growth of the database content in terms of number of entries in the three successive releases.
Ribosomal RNA genes are DNA sequences coding for ribosomal RNA. In most eukaryotes, 5S and 18S-5.8S-26S (also termed 35S or 45S) rDNA are separated (in the same chromosome or in different chromosomes), tandemly arranged, and clustered in highly repetitive arrays (1); however, exceptions are known in yeast (Saccharomyces cerevisiae), some bryophytes (the liverwort Marchantia polymorpha), some gymnosperms such as Ginkgo or angiosperms such as the Asteraceae genus Artemisia, in which all ribosomal RNA genes are organised as a single operon (2).
Fluorescent in situ hybridisation is widely used for mapping DNA sequences to their position in the genome, enabling characterisation of chromosomes. The most commonly used probes for FISH in plants are the ribosomal RNA genes (rDNA).
NOTE: This database is not providing any rDNA sequence data, but information about rDNA loci number and position in chromosomes. If you are interested in sequence data, you can consult other databases on this topic listed at LINKS