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Is there any one DNA sequence shared by all or most viruses?

I highly doubt there is mainly because of how different all of them are, but it's still worth a try.

Thanks

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  • $\begingroup$ What length of sequence did you have in mind? $\endgroup$ – canadianer Feb 23 '15 at 20:23
  • $\begingroup$ Around 4 to 8 nucleotides would be perfect. $\endgroup$ – CDB Feb 23 '15 at 20:32
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    $\begingroup$ Statistically it seems very likely that every organism would share a 4 nucleotide sequence. $\endgroup$ – canadianer Feb 23 '15 at 20:50
  • $\begingroup$ Very true. I'm looking specifically for any sort of shared sequence that is necessary for the survival of all viruses. At first I thought (for RNA viruses at least) it would be some sequence in a gene that codes for reverse transcriptase, however I have yet to find such a sequence. Any suggestions for a sequence like this or any other would be very greatly appreciated, so feel free to mention any ideas you might think of. $\endgroup$ – CDB Feb 23 '15 at 20:57
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There are commonalities within certain related viral families. But no, there are no universal viral genes, there are many reasons for this:

  1. Viral genomes in general are much smaller than the average cell genome and the pressure for selection against extraneous genes is high due to the need to be able to replicate as fast as possible within the host cell. This also allows for rapid evolutionary rates due to the sheer mass of viruses creates and spread through a given host.

  2. There are viruses that infect wildly different hosts and thus require highly divergent entrance mechanisms and strategies. Due to this difference, there would be no need for the bacteriophage for instance to share the same proteins or genes with those of HIV or another human virus.

  3. It is possible that viruses have evolved multiple times throughout the history of life, this is however not confirmed as of this time. If it is true however, then it would preclude the possibility of universal viral genes as they would not share a common homology.(Though viruses may be able to mix their genetic material by sheer chance, if they share a common host.)

  4. Viruses, by definition lack the common replication, translation and generally, transcription machinery that is shared by their cellular hosts. Thus, they do not have this source of common genes, as living organisms do.

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No, virus are polyphyletic and there are no genes that are common to all viruses. There may be similarities in capsid structure due to convergent evolution, but these are not universal. See Moreira and López-García (2009) for further detail.

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