Clockwise from top left: TEM of avian coronavirus, polio virus, bacteriophage Qβ, ebolavirus, tobacco mosaic virus, influenzavirus A, rotavirus, HIV-1. Center: homologous RT and RdRps with conserved palm domain.
Virus classification
(unranked):
Virus
Realm:
Riboviria
Kingdoms
Orthornavirae
Pararnavirae
Riboviria is a realm of viruses that includes all viruses that use a homologous RNA-dependent polymerase for replication. It includes RNA viruses that encode an RNA-dependent RNA polymerase, as well as reverse-transcribing viruses (with either RNA or DNA genomes) that encode an RNA-dependent DNA polymerase. RNA-dependent RNA polymerase (RdRp), also called RNA replicase, produces RNA (ribonucleic acid) from RNA. RNA-dependent DNA polymerase (RdDp), also called reverse transcriptase (RT), produces DNA (deoxyribonucleic acid) from RNA. These enzymes are essential for replicating the viral genome and transcribing viral genes into messenger RNA (mRNA) for translation of viral proteins.
Riboviria was established in 2018 to accommodate all RdRp-encoding RNA viruses and was expanded a year later to also include RdDp-encoding retroviruses. These two groups of viruses are assigned to two separate kingdoms: Orthornavirae for RdRp-encoding RNA viruses, and Pararnavirae for RdDp-encoding viruses, i.e. all reverse-transcribing viruses. While the realm has few prokaryotic viruses, it includes most eukaryotic viruses, including most human, animal, and plant viruses, however, metagenomic studies are changing this perspective.
Many of the most widely known viral diseases are caused by viruses in Riboviria, which includes coronaviruses, ebola virus, HIV, influenza viruses, and the rabies virus. These viruses and others have been prominent throughout history, including Tobacco mosaic virus, which was the first virus to be discovered. Many reverse transcribing viruses notably become integrated into the genome of their host as part of their replication cycle. As a result of that, it is estimated that about 7–8% of the human genome originates from these viruses.
Riboviria is a realm of viruses that includes all viruses that use a homologous RNA-dependent polymerase for replication. It includes RNA viruses that...
taxa. In 2018, the realm Riboviria was established and initially included the three RNA virus groups. A year later, Riboviria was expanded to also include...
polymerase are believed to form a monophyletic group, known as the realm Riboviria. The majority of such RNA viruses fall into the kingdom Orthornavirae...
sedis genera are recognized: Realms: Adnaviria Duplodnaviria Monodnaviria Riboviria Ribozyviria Varidnaviria Incertae sedis classes: Naldaviricetes Incertae...
recombination, and reassortment. Viruses in Orthornavirae belong to the realm Riboviria. They are descended from a common ancestor that may have been a non-viral...
Another proposed family of the phylum is unassigned Polymycoviridae in Riboviria. The following classes are recognized: Duplopiviricetes Pisoniviricetes...
Orthocoronavirinae, in the family Coronaviridae, order Nidovirales and realm Riboviria. They are enveloped viruses with a positive-sense single-stranded RNA...
megataxonomic framework, filling all principal taxonomic ranks, for realm Riboviria". International Committee on Taxonomy of Viruses (ICTV). Retrieved 2020-05-21...
transcriptase, are classified into the kingdom Pararnavirae in the realm Riboviria. DNA viruses are ubiquitous worldwide, especially in marine environments...
mistakenly classified Deltavirus within the then newly established realm, Riboviria. In 2019, this error was rectified and Deltavirus returned to its original...
Matonaviridae remains part of the realm that it was already in as Togaviridae, Riboviria, because of its RNA genome and RNA dependent RNA polymerase. In 2020,...
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