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|
|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
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.
Judging by the recently increasing number of publications (more than 50% of the publications listed in the database are from the last ten years) the interest in these data is high and there is a need for compilation, as they are often difficult to find, scattered in a variety of journals. With this purpose, the database holds rDNA loci information on angiosperms, gymnosperms, bryophytes and pteridophytes from papers already published or in press up to June 2013. Regular updates are planned.
Database content in Release 2.0. In land plants, 95.5% of data belong to angiosperms, 4.05% to gymnosperms, 0.18% to bryophytes and 0.21% to pteridophytes. Within angiosperms, most of them (64.25%) are core eudicots, only 0.22% are basal eudicots, and 35.53% are monocots.
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