Origin of viruses: primordial replicators recruiting capsids from hosts

@article{Krupovic2019OriginOV,
  title={Origin of viruses: primordial replicators recruiting capsids from hosts},
  author={Mart Krupovic and Valerian V. Dolja and Eugene V. Koonin},
  journal={Nature Reviews Microbiology},
  year={2019},
  volume={17},
  pages={449-458}
}
Viruses are ubiquitous parasites of cellular life and the most abundant biological entities on Earth. It is widely accepted that viruses are polyphyletic, but a consensus scenario for their ultimate origin is still lacking. Traditionally, three scenarios for the origin of viruses have been considered: descent from primordial, precellular genetic elements, reductive evolution from cellular ancestors and escape of genes from cellular hosts, achieving partial replicative autonomy and becoming… 
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References

SHOWING 1-10 OF 156 REFERENCES
Multiple origins of viral capsid proteins from cellular ancestors
TLDR
It is suggested that, although the replication modules of at least some classes of viruses might descend from primordial selfish genetic elements, bona fide viruses evolved on multiple, independent occasions throughout the course of evolution by the recruitment of diverse host proteins that became major virion components.
Virus World as an Evolutionary Network of Viruses and Capsidless Selfish Elements
TLDR
The concept of a greater virus world which forms an evolutionary network that is held together by shared conserved genes and includes both bona fide capsid-encoding viruses and different classes of capsidless replicons is developed.
A virocentric perspective on the evolution of life
The origin of viruses.
The precellular scenario of genovirions
A new hypothesis of the ancestors of contemporary viruses, the genovirions is proposed. This concept emphasizes the close connection between the evolution of viruses and the proto-cells. Recent and
The Origin of Virions and Virocells: The Escape Hypothesis Revisited
TLDR
This updated version of the escape hypothesis suggests a working program to tackle the question of virus origin, and shows how accumulating data in structural biology combined to new virus definitions allow rejecting the first two hypotheses.
A phylogenomic data-driven exploration of viral origins and evolution
TLDR
An ancient origin of the “viral supergroup” is established and the existence of widespread episodes of horizontal transfer of genetic information is established if one considers viruses to have originated from ancient cells and not from modern counterparts.
...
...