Scripps Florida scientists show 'lifeless' prions capable of evolutionary change

http://www.eurekalert.org/pub_releases/2009-12/sri-sfs122909.phpI don't know about you, but this seems like some pretty heavy news.

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Who are we? We find that we live on an insignificant planet of a humdrum star lost in a galaxy tucked away in some forgotten corner of a universe in which there are far more galaxies than people
-Carl SaganFor me, it is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring.
-Carl Sagan

Darwinian Evolution of Prions in Cell CultureJiali Li, Shawn Browning, Sukhvir P. Mahal, Anja M. Oelschlegel, Charles Weissmann*Abstract: Prions are infectious proteins consisting mainly of PrPSc, a β sheet—rich conformer of the normal host protein PrPC, and occur in different strains. Strain identity is thought to be encoded by PrPSc conformation. We found that biologically cloned prion populations gradually became heterogeneous by accumulating "mutants," and selective pressures resulted in the emergence of different mutants as major constituents of the evolving population. Thus, when transferred from brain to cultured cells, "cell-adapted" prions outcompeted their "brain-adapted" counterparts, and the opposite occurred when prions were returned from cells to brain. Similarly, the inhibitor swainsonine selected for a resistant substrain, whereas, in its absence, the susceptible substrain outgrew its resistant counterpart. Prions, albeit devoid of a nucleic acid genome, are thus subject to mutation and selective amplification.Department of Infectology, Scripps Florida, 130 Scripps Way, Jupiter, FL 33458, USA========Blog:Evolution without genes - prions can evolve and adapt tooIf you search for decent definitions of evolution, the chances are that you'll see genes mentioned somewhere. The American Heritage Dictionary talks about natural selection acting on "genetic variation", Wikipedia discusses "change in the genetic material of a population... through successive generations", and TalkOrigins talks about changes that are inherited "via the genetic material". But, as the Year of Darwin draws to a close, a new study suggests that all of these definitions are too narrow.Jiali Li from the Scripps Institute in Florida has found that prions - the infectious proteins behind mad cow disease, CJD and kuru - are capable of Darwinian evolution, all without a single strand of DNA or its sister molecule RNA. Read the rest here.========Good subject for a thread.

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Just shows how evolution is pretty much a given when the circumstances are correct.Almost as if it is a 'natural law' that if things can evolve they will.

This is clearly a big exaggeration as the blog itself goes on to point out in reference to whether this means prions are alive ... The differential propagation of the PrP conformations certainly satisfies most of the criteria for evolution, arguably in a Lamarckian mode. But to say there is no role for nucleic acids is to ignore the source of the prion proteins.TTFN,WK

I tried to view the paper itself over at Science Express, but it was one which necessitated a paid subscription. So you are saying this is yet another "media hype"? That would suck if it was.

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Who are we? We find that we live on an insignificant planet of a humdrum star lost in a galaxy tucked away in some forgotten corner of a universe in which there are far more galaxies than people
-Carl SaganFor me, it is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring.
-Carl Sagan

No I'm not saying that, just that the blog is going overboard emphasising 'all without a single strand of DNA or its sister molecule RNA', since these molecules are required for the initial production of the Prion proteins.I have vague memories of other possible candidates for this sort of 'evolution' but I can't remember the details. I think it was to do with the propagation of different structural forms of clays.TTFN,WK