''Megaviricetes'' is a class of
virus
A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea.
Since Dmitri Ivanovsky's 1 ...
es.
The class contains
giant virus
A giant virus, sometimes referred to as a girus, is a very large virus, some of which are larger than typical bacteria. All known giant viruses belong to the phylum ''Nucleocytoviricota''.
Description
While the exact criteria as defined in the s ...
es, all of which are nucleocytoplasmic large DNA viruses that are assigned to the phylum ''
Nucleocytoviricota
''Nucleocytoviricota'' is a phylum of viruses. Members of the phylum are also known as the nucleocytoplasmic large DNA viruses (NCLDV), which serves as the basis of the name of the phylum with the suffix - for virus phylum. These viruses are refe ...
''. Members of the Megaviricetes typically have genomes that are much larger than viruses assigned to other taxa, and also encode genes involved in
DNA repair
DNA repair is a collection of processes by which a cell identifies and corrects damage to the DNA molecules that encode its genome. In human cells, both normal metabolic activities and environmental factors such as radiation can cause DNA dam ...
,
DNA replication
In molecular biology, DNA replication is the biological process of producing two identical replicas of DNA from one original DNA molecule. DNA replication occurs in all living organisms acting as the most essential part for biological inheritanc ...
,
transcription
Transcription refers to the process of converting sounds (voice, music etc.) into letters or musical notes, or producing a copy of something in another medium, including:
Genetics
* Transcription (biology), the copying of DNA into RNA, the fir ...
,
translation
Translation is the communication of the Meaning (linguistic), meaning of a #Source and target languages, source-language text by means of an Dynamic and formal equivalence, equivalent #Source and target languages, target-language text. The ...
, and other processes that viruses in other taxa usually lack. As well, the virus particles (virions) of some members of ''Megaviricetes'' are much larger in size than for other viruses, and can be larger than some
bacteria
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...
.
Orders
The following orders are recognized:
* ''
Algavirales
''Phycodnaviridae'' is a family of large (100–560 kb) double-stranded DNA viruses that infect marine or freshwater eukaryotic algae. Viruses within this family have a similar morphology, with an icosahedral capsid (polyhedron with 20 fa ...
''
* ''
Imitervirales
''Mimiviridae'' is a family of viruses. Amoeba and other protists serve as natural hosts. The family is divided in up to 4 subfamilies., UCPMS ID: 1889607PDF/ref> Fig. 4 and §Discussion: "Considering that tupanviruses comprise a sister gr ...
''
* ''
Pimascovirales
''Pimascovirales'' is an order of viruses. The term is a portmanteau of a portmanteau of pitho-, irido-, marseille-, and ascoviruses.
Families
The following families are recognized:
* '' Ascoviridae''
* ''Iridoviridae''
* ''Marseilleviridae
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''
References
Virus classes
{{Virus-stub