Orthornavirae
Orthornavirae is a kingdom of viruses that have genomes made of ribonucleic acid (RNA) and which encode an RNA-dependent RNA polymerase (RdRp). The RdRp is used to transcribe the viral RNA genome into messenger RNA (mRNA) and to replicate the genome. Viruses in this kingdom also share a number of characteristics involving evolution, including high rates of genetic mutations, recombinations, and reassortments.

Viruses in "Orthornavirae" belong to the realm "Riboviria". They are descended from a common ancestor that may have been a non-viral molecule that encoded a reverse transcriptase instead of an RdRp for replication. The kingdom is subdivided into five phyla that separate member viruses based on their genome type, host range, and genetic similarity. Viruses with three genome types are included: positive-strand RNA viruses, negative-strand RNA viruses, and double-stranded RNA viruses. 

Many of the most widely known viral diseases are caused by RNA viruses in the kingdom, which includes coronaviruses, the Ebola virus, influenza viruses, the measles virus, and the rabies virus. The first virus to be discovered, tobacco mosaic virus, belongs to the kingdom. In modern history, RdRp-encoding RNA viruses have caused numerous disease outbreaks, and they infect many economically important crops. Most eukaryotic viruses, including most human, animal, and plant viruses, are RdRp-encoding RNA viruses. In contrast, there are relatively few prokaryotic viruses in the kingdom.
Q808
virus
Concept
Q11053
ribonucleic acid
Concept
Q180618
encode
Concept
Q2919111
RNA-dependent RNA polymerase
Concept
Q177900
transcribe
Concept
Q188928
messenger RNA
Concept
Q3933202
replicate
Concept
Q2066554
evolution
Concept
Q42918
genetic mutations
Concept
Q211675
recombinations
Concept
Q2004399
reassortments
Concept
Q62002503
Riboviria
MISC
Q333018
common ancestor
Concept
Q28774
reverse transcriptase
Concept
Q9094478
positive-strand RNA viruses
Concept
Q57737752
negative-strand RNA viruses
MISC
Q3307900
double-stranded RNA viruses
Concept
Q89469904
coronaviruses
Concept
Q8064876
Ebola virus
Concept
Q287246
influenza viruses
Concept
Q573943
measles virus
Concept
Q698976
rabies virus
Concept
Q332874
tobacco mosaic virus
Concept
Q19088
eukaryotic
Concept
Q19081
prokaryotic
Concept
Q92190862
Orthornavirae
MISC
Q92190862
Orthornavirae
MISC
parent taxon