Varidnaviria

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Varidnaviria is a realm of viruses that encompasses a diverse group of double-stranded DNA viruses. These viruses are characterized by their unique virion structure, which includes an icosahedral capsid. The realm Varidnaviria is one of the major divisions in the classification of viruses and includes several families that infect a wide range of hosts, from bacteria to eukaryotes.

Classification

Varidnaviria is divided into two major kingdoms:

• Bamfordvirae
• Helvetiavirae

Bamfordvirae

The kingdom Bamfordvirae includes viruses that infect both eukaryotic and prokaryotic organisms. Notable families within this kingdom include:

• Nucleocytoviricota
• Pithoviridae
• Ascoviridae

Helvetiavirae

The kingdom Helvetiavirae primarily consists of viruses that infect eukaryotic hosts. This kingdom includes the following families:

• Mimiviridae
• Phycodnaviridae
• Iridoviridae

Structure

Viruses in the realm Varidnaviria possess a distinctive icosahedral capsid structure. The capsid is composed of protein subunits that form a symmetrical shell around the viral genome. This structure is crucial for the protection of the viral DNA and for the infection process.

Genome

The genome of Varidnaviria viruses is typically composed of double-stranded DNA. The size of the genome can vary significantly among different families within the realm, ranging from tens of kilobases to over a megabase.

Evolution

Varidnaviria viruses are believed to have a long evolutionary history, with evidence suggesting that they have co-evolved with their hosts over millions of years. The diversity within this realm indicates multiple ancient origins and extensive genetic exchange between different viral lineages.

Hosts

Varidnaviria viruses infect a wide range of hosts, including:

• Bacteria
• Archaea
• Eukaryotes

Importance

The study of Varidnaviria is important for understanding viral evolution, the mechanisms of viral infection, and the impact of viruses on ecosystems. These viruses play significant roles in regulating microbial populations and influencing biogeochemical cycles.

See also

• Virus classification
• Virology
• DNA virus