Bacteriophage - Classification

Classification

The dsDNA tailed phages, or Caudovirales, account for 95% of all the phages reported in the scientific literature, and possibly make up the majority of phages on the planet. However, other phages occur abundantly in the biosphere, with different virions, genomes and lifestyles. Phages are classified by the International Committee on Taxonomy of Viruses (ICTV) according to morphology and nucleic acid.

Nineteen families are currently recognised that infect bacteria and archaea. Of these, only two families have RNA genomes and only five families are enveloped. Of the viral families with DNA genomes, only two have single-stranded genomes. Eight of the viral families with DNA genomes have circular genomes, while nine have linear genomes. Nine families infect bacteria only, nine infect archaea only, and one (Tectiviridae) infects both bacteria and archaea.

ICTV classification of prokaryotic (bacterial and archaeal) viruses
Order Family Morphology Nucleic acid Examples
Caudovirales Myoviridae Nonenveloped, contractile tail Linear dsDNA T4 phage
Siphoviridae Nonenveloped, noncontractile tail (long) Linear dsDNA λ phage, Bacteriophage T5
Podoviridae Nonenveloped, noncontractile tail (short) Linear dsDNA T7 phage
Ligamenvirales Lipothrixviridae Enveloped, rod-shaped Linear dsDNA Acidianus filamentous virus 1
Rudiviridae Nonenveloped, rod-shaped Linear dsDNA Sulfolobus islandicus rod-shaped virus 1
Unassigned Ampullaviridae Enveloped, bottle-shaped Linear dsDNA
Bicaudaviridae Nonenveloped, lemon-shaped Circular dsDNA
Clavaviridae Nonenveloped, rod-shaped Circular dsDNA
Corticoviridae Nonenveloped, isometric Circular dsDNA
Cystoviridae Enveloped, spherical Segmented dsRNA
Fuselloviridae Nonenveloped, lemon-shaped Circular dsDNA
Globuloviridae Enveloped, isometric Linear dsDNA
Guttavirus Nonenveloped, ovoid Circular dsDNA
Inoviridae Nonenveloped, filamentous Circular ssDNA
Leviviridae Nonenveloped, isometric Linear ssRNA MS2, Qβ
Microviridae Nonenveloped, isometric Circular ssDNA ΦX174
Plasmaviridae Enveloped, pleomorphic Circular dsDNA
Tectiviridae Nonenveloped, isometric Linear dsDNA

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