REPOST: Viruses and The Tree of Life

Posted by ERV on July 22, 2008
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This is a repost from the old ERV. A retrotransposed ERV :P I dont trust them staying up at Blogger, and the SEED overlords are letting me have 4 reposts a week, so Im gonna take advantage of that!

I am going to try to add more comments to these posts for the old readers– Think of these as ‘directors cut’ posts ;)

Gimme a sec. Youll see why Im reposting this. *melts with embarrassment*

Me: “OMG! My boyfriend published another paper!!”

Bossman: “Ugh. Do you have any idea how old he is?”

Me: “Our love, it is forbidden.”

My virus boyfriend Patrick Forterre is still fighting the good fight for viruses:

Redefining Viruses: Lessons from Mimivirus

Why the hell arent the most abundant creatures on the planet included in the tree of life??

Viruses arent just wads of selfish genes. They are an organism. They contribute massively to the evolution of ‘life’ on this planet.

We arent slack-jawed TARD Creationists pointing at a Panda Bear slurring “Dat der is a BEAR kiiiind.” We use genetics to establish phylogenetic trees, ergo, who is related to whom. Why do we point to viruses and drool “It aint ALIVE! It caint go in deh tree!”

It doesnt make any sense. Like having a ribosome imparts an organism with a ‘soul’ that allows it to be considered ‘alive’ and included in Earths evolutionary tree of life.

But that is the stickler for including viruses in the tree. Usually its the ribosomal sequence thats used to compare amoebas to oak trees. And viruses dont have them. Viruses really dont have anything in common with cells (so much for the “But viruses r just de-evolved CELLS!!” hypothesis) so how can we attach them to the Tree?

Forterre suggests that we just use the protein that all viruses have in common, capsid, to create a mirror tree. Like a reflection in a graveyard pond, a Tree of Undead Viruses.

Hmm.

Its a start. But I do not like. I dont see the viral world evolving like a mirror Tree of Life with viruses evolving with their hosts in an alternate dimension. I see The Tree of Life and the Tree of Undead Viruses hopelessly intertwined– in the same dimension– we can detect where we got protein A and protein B from viruses and where bactereophages stole protein C and protein D from their hosts or one another. I dont think Forterre would suggest that the trees are isolated, as it appeared in a diagram in this paper, but that is going to be the outcome if you compare Ribosomal Encoding Organisms to Capsid Encoding Organisms.

Meh.

It is a start :)

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Comments

  1. #1 wazza
    July 23, 2008

    To me, the best analogy would be a tree of life (Ribosomal) with a vine growing up it, curling around branches, stringing from branch to branch, splitting into smaller and smaller vines as it goes, and dependent on the tree for its support, but sometimes also holding up saggy parts of the tree by binding it together with vines…

    Plus, “Vine of Viruses” is deliciously alliterative.

  2. #2 Chris (Fabulously in the City)
    July 23, 2008

    Thanks for the repost! I actually like them :-)

  3. #3 Eric
    July 23, 2008

    Seeing as there is no actual physical property to life, why not. After all, viruses evolve, there is no reason not to have a viral tree of life.

  4. #4 wazza
    July 24, 2008

    I read about a museum in England where one of those Victorian-era explorer-types had gathered examples of tools – that he had actually seen in use – and assembled a sequence from a stick out to just about every modern tool, gradual modifications enhancing their utility…

  5. #5 Tatarize
    July 24, 2008

    Should we also include mitochondria? Lets make it really complicated and say that this branch is part of this branch and all of the related subbranches. While we’re at it, lets stop doing disservice to trees and count all the hybridizations of this species comes from this species and this species.

    Pretty much every branch has a fairly different tree of life. Some branches will be branching off, some branching back in, some infecting other branches for a few million years. — As far as I’m concerned life is defined by it’s ability to evolve but if you include all the things we should include our little metaphor breaks down and we can’t have that. What next is DNA not just a stupid molecule that sits there and lets crap from the cytoplasm copy down some nifty protein sequences? Truth makes science hard.

  6. #6 John Kwok
    July 26, 2008

    Hi Abbie,

    So who is right, Eugene Koonin or Thomas Cavalier-Smith? I appreciate how messy it would be trying to do cladistics based on molecular sequence data from viral DNA. Any thoughts?

    Your former paleobiologist ami,

    JOhn