Fish polyomaviruses belong to two distinct evolutionary lineages

Area of Science:

• Virology
• Evolutionary Biology
• Marine Biology

Background:

• Polyomaviridae are diverse circular, double-stranded DNA viruses found in many animal hosts.
• Understanding polyomavirus evolution and ecology is crucial for assessing their pathogenicity.

Purpose of the Study:

• To identify novel polyomaviruses in marine animals.
• To investigate the evolutionary dynamics of polyomaviruses across different host types.

Main Methods:

• High-throughput sequencing was employed to identify viral sequences.
• Phylogenetic analysis was used to determine evolutionary relationships.

Main Results:

• A novel polyomavirus was identified in the emerald notothen (Trematomus bernacchii) from the Ross Sea, Antarctica.
• This discovery expands the known diversity of fish-associated polyomaviruses.
• Phylogenetic analysis indicated three main evolutionary clades of polyomaviruses, with fish viruses not forming a monophyletic group and belonging to two distinct lineages.
• Evidence suggests domain gain and loss in the viral large T protein during fish polyomavirus evolution.

Conclusions:

• Polyomaviruses exhibit diverse evolutionary pathways across terrestrial and aquatic hosts.
• Fish-associated polyomaviruses represent ancient and divergent lineages.
• The evolution of key viral proteins like the large T antigen is shaped by domain dynamics.