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Portogloboviridae  !

Portogloboviridae is a proposed family of double-stranded DNA (dsDNA) viruses that infect archaea. While it is suggested to belong to the realm Varidnaviria, the International Committee on Taxonomy of Viruses (ICTV) has classified it as incertae sedis, meaning it is uncertain or unassigned to a specific taxonomic rank.


  •  Portogloboviridae viruses have icosahedral-shaped capsids and are enveloped, with a diameter ranging from 83 to 87 nanometers. Their genetic material consists of circular double-stranded DNA (dsDNA) with a length of 20,222 base pairs. The genome contains 45 open reading frames (ORFs), occupying 89.1% of the genome, and the ORFs are typically short, averaging 103 codons in length.
  •  The virions contain 10 proteins, ranging from 20 to 32 kDa. Eight of these proteins form the capsid, while two are associated with the viral envelope. One of the envelope proteins is a single jelly roll (SJR) capsid protein, which plays a role in the virus structure.
  •  Viral entry occurs via penetration into the host cell, and the virus replicates through a chronic infection without undergoing a lytic cycle, meaning the host cell is not destroyed in the process.

Evolutionary Importance :

The Portogloboviridae viruses, together with Halopanivirales, are considered evolutionarily significant in understanding the origins of the Varidnaviria realm. These viruses are seen as relics of the earliest viruses within this realm and may have infected the last universal common ancestor (LUCA), possibly originating before LUCA itself.

Their evolutionary connection to other Varidnaviria viruses has been proposed to follow this lineage:

  • Varidnaviria
    • Portogloboviridae
      • Helvetiavirae
      • Bamfordvirae
  •  This suggests that Portogloboviridae could provide critical insights into the early evolution of viruses and their relationship to more complex viral families within the Varidnaviria realm.