Marine origin of retroviruses in the early Palaeozoic Era
Pakorn Aiewsakun & Aris Katzourakis
Nature Communications 8, Article number: 13954 (2017)
Phylogenetics Retrovirus
Received: 13 May 2016 Accepted: 16 November 2016 Published online: 10 January 2017
Abstract
Very little is known about the ancient origin of retroviruses, but owing to the discovery of their ancient endogenous viral counterparts, their early history is beginning to unfold. Here we report 36 lineages of basal amphibian and fish foamy-like endogenous retroviruses (FLERVs). Phylogenetic analyses reveal that ray-finned fish FLERVs exhibit an overall co-speciation pattern with their hosts, while amphibian FLERVs might not. We also observe several possible ancient viral cross-class transmissions, involving lobe-finned fish, shark and frog FLERVs. Sequence examination and analyses reveal two major lineages of ray-finned fish FLERVs, one of which had gained two novel accessory genes within their extraordinarily large genomes. Our phylogenetic analyses suggest that this major retroviral lineage, and therefore retroviruses as a whole, have an ancient marine origin and originated together with, if not before, their jawed vertebrate hosts >450 million years ago in the Ordovician period, early Palaeozoic Era.
Acknowledgements
P.A. is funded by the Royal Thai Government, A.K. is funded by the Royal Society. The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript. We thank members of the research group for constructive comments and discussions.
Author information
Affiliations
Department of Zoology, University of Oxford, Oxford OX1 3PS, UK
Pakorn Aiewsakun & Aris Katzourakis
Contributions
P.A. and A.K. conceived the project, performed the analyses, interpreted the results and wrote the paper.
Competing interests
The authors declare no competing financial interests.
Corresponding author
Correspondence to Aris Katzourakis.
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