Duplodnaviria

Duplodnaviria
Illustrated sample of Duplodnaviria virions
Virus classification
(unranked):	Virus
Realm:	Duplodnaviria
Kingdom:	Heunggongvirae
Subtaxa
See text
Synonyms[1][2]
HK97-like group HK97 major capsid protein supermodule

Duplodnaviria is a realm of viruses that includes all double-stranded DNA viruses that encode the HK97 fold major capsid protein. The HK97 fold major capsid protein (HK97 MCP) is the primary component of the viral capsid, which stores the viral deoxyribonucleic acid (DNA). Viruses in the realm also share a number of other characteristics, such as an icosahedral capsid, an opening in the viral capsid called a portal, a protease enzyme that empties the inside of the capsid prior to DNA packaging, and a terminase enzyme that packages viral DNA into the capsid.

Duplodnaviria was established in 2019 based on the shared characteristics of viruses in the realm. There are two groups of viruses in Duplodnaviria: tailed bacteriophages of the order Caudovirales, which infect prokaryotes, and herpesviruses of the order Herpesvirales, which infect animals. Tailed bacteriophages are very diverse and ubiquitous worldwide, and they may be the oldest lineage of viruses. Herpesviruses either share a common ancestor with tailed bacteriophages or are a breakaway group from within Caudovirales.

Tailed bacteriophages are important in marine ecology by recycling nutrients in organic material from their hosts and are the focus of much research, and herpesviruses are associated with a variety of diseases in animals, including humans. A common feature among viruses in Duplodnaviria is that many are able to persist in their host for long periods of time without replicating while still being able to resurface in the future. Examples of this include the herpes simplex virus, which causes recurring infections, and the varicella zoster virus, which initially causes chickenpox early in life then shingles later in life.