RNA-DNA Virus Hybrid Found

[Shiloh]

Source: http://the-scientist.com/2012/04/20/rna-dna-virus-hybrid-found/

RNA-DNA Virus Hybrid Found
Researchers discovered a virus produced from recombination between RNA and DNA viruses, suggesting a possible new mechanism of virus evolution.
By Sabrina Richards | April 20, 2012

?It?s a mythological beast of a virus, but it actually exists,? virologist Ken Stedman told Nature of the virus hybrid his team discovered in a volcanic hot spring. Stedman?s team from Portland State University sequenced the DNA genome of the virus, and found that contained sequences encoding proteins from an RNA virus, according to their report published yesterday (April 19) in Biology Direct...

 

[sharon sanders]

Re: RNA-DNA Virus Hybrid Found

A novel virus genome discovered in an extreme environment suggests recombination between unrelated groups of RNA and DNA viruses
Geoffrey S Diemer and Kenneth M Stedman
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Biology Direct 2012, 7:13 doi:10.1186/1745-6150-7-13


Published: 19 April 2012
Abstract (provisional)
Background
Viruses are known to be the most abundant organisms on earth, yet little is known about their collective origin and evolutionary history. With exceptionally high rates of genetic mutation and mosaicism, it is not currently possible to resolve deep evolutionary histories of the known major virus groups. Metagenomics offers a potential means of establishing a more comprehensive view of viral evolution as vast amounts of new sequence data becomes available for comparative analysis.

Results
Bioinformatic analysis of viral metagenomic sequences derived from a hot, acidic lake revealed a circular, putatively single-stranded DNA virus encoding a major capsid protein similar to those found only in single-stranded RNA viruses. The presence and circular configuration of the complete virus genome was confirmed by inverse PCR amplification from native DNA extracted from lake sediment. The virus genome appears to be the result of a RNA-DNA recombination event between two ostensibly unrelated virus groups. Environmental sequence databases were examined for homologous genes arranged in similar configurations and three similar putative virus genomes from marine environments were identified. This result indicates the existence of a widespread but previously undetected group of viruses.


Conclusions
This unique viral genome carries implications for theories of virus emergence and evolution, as no mechanism for interviral RNA-DNA recombination has yet been identified, and only scant evidence exists that genetic exchange occurs between such distinct virus lineages. Reviewers This article was reviewed by EK, MK (nominated by PF) and AM. For the full reviews, please go to the Reviewers' comments section.

http://www.biology-direct.com/content/7/1/13/abstract