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28S ribosomal RNA is the structural ribosomal RNA (rRNA) for the large subunit (LSU) of eukaryotic cytoplasmic ribosomes, and thus one of the basic components of all eukaryotic cells. It has a size of 25S in plants and 28S in mammals, hence the alias of 25S–28S rRNA.
Combined with
28S ribosomal RNA is the structural ribosomal RNA (rRNA) for the large subunit (LSU) of eukaryotic cytoplasmic ribosomes, and thus one of the basic components of all eukaryotic cells. It has a size of 25S in plants and 28S in mammals, hence the alias of 25S–28S rRNA.
Combined with 5.8S rRNA
In molecular biology, the 5.8S ribosomal RNA (5.8S rRNA) is a non-coding RNA component of the large subunit of the Eukaryote, eukaryotic ribosome and so plays an important role in translation (genetics), protein translation. It is Transcription ( ...
to the 5' side, it is the eukaryotic nuclear homologue of the prokaryotic 23S and mitochondrial 16S ribosomal RNAs.
Use in phylogeny
The genes coding for 28S rRNA are referred to as 28S rDNA. The comparison of thesequences
In mathematics, a sequence is an enumerated collection of objects in which repetitions are allowed and order matters. Like a set, it contains members (also called ''elements'', or ''terms''). The number of elements (possibly infinite) is called t ...
from these genes are sometimes used in molecular analysis to construct phylogenetic tree
A phylogenetic tree (also phylogeny or evolutionary tree Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA.) is a branching diagram or a tree showing the evolutionary relationships among various biological spec ...
s, for example in protist
A protist () is any eukaryotic organism (that is, an organism whose cells contain a cell nucleus) that is not an animal, plant, or fungus. While it is likely that protists share a common ancestor (the last eukaryotic common ancestor), the exc ...
s, fungi
A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from ...
, insect
Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pairs ...
s, arachnid
Arachnida () is a class of joint-legged invertebrate animals (arthropods), in the subphylum Chelicerata. Arachnida includes, among others, spiders, scorpions, ticks, mites, pseudoscorpions, harvestmen, camel spiders, whip spiders and vinegaroon ...
s, tardigrade
Tardigrades (), known colloquially as water bears or moss piglets, are a phylum of eight-legged segmented micro-animals. They were first described by the German zoologist Johann August Ephraim Goeze in 1773, who called them Kleiner Wasserbär ...
s, and vertebrate
Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, ...
s.
Structure
The 28S rRNA is typically 4000–5000 nt long. Some eukaryotes cleave 28S rRNA into two parts before assembling both into the ribosome, a phenomenon termed the "hidden break".Databases
Severaldatabase
In computing, a database is an organized collection of data stored and accessed electronically. Small databases can be stored on a file system, while large databases are hosted on computer clusters or cloud storage. The design of databases sp ...
s provide alignments and annotations
An annotation is extra information associated with a particular point in a document or other piece of information. It can be a note that includes a comment or explanation. Annotations are sometimes presented in the margin of book pages. For anno ...
of LSU rRNA sequences for comparative
In general linguistics, the comparative is a syntactic construction that serves to express a comparison between two (or more) entities or groups of entities in quality or degree - see also comparison (grammar) for an overview of comparison, as wel ...
purposes:
* RDP, the Ribosomal Database Project;
* SILVA, a ribosomal RNA gene database project.
References
{{DEFAULTSORT:28s Ribosomal Rna Ribosomal RNA