[FoRK] Putting a little fear of Evolution in folks....
mattj at newsblip.com <
mattj at newsblip.com
> on >
Wed Mar 15 12:33:52 PST 2006
Quoting Joe Barrera <joe at barrera.org>:
> Besides, are viruses* alive?
There's a terrific article in Discover this month...
"A monstrous discovery suggests that viruses, long regarded as lowly
evolutionary latecomers, may have been the precursors of all life on
DISCOVER Vol. 27 No. 03 | March 2006 | Biology & Medicine
"We have a lot of evidence with Mimivirus that the virus phylum is at
least as old as the other branches of life and that viruses were
involved very early on in the evolutionary emergence of life."
That represents a radical change in thinking about life's origins:
Viruses, long thought to be biology's hitchhikers, turn out to have
been biology's formative force.
The implications of [that analysis] are truly radical: that Mimi, or a
Mimi-like ancestor, emerged prior to the three other domains and played
a key role in inventing the very cells of which humans and all complex
cellular life-forms are made.
It is a difficult concept to get one's head around. Parasites, to us,
are derivative, necessarily descendant from the biological entities
they depend on for life. But simple does not always mean less evolved.
Mimi's outsize complement of genes?so large that the virus is
tantalizingly close to being an independent organism?suggest to many
scientists that Mimivirus underwent reductive evolution early on and
shed some of its genome, including the genes necessary to replicate on
"With Mimi, we've captured by chance a picture of an organism that was
undergoing such a reduction, evolving toward fewer genes," says
Claverie. "This guy just retained more ancestral features than others."
Biologists, Claverie says, can no longer view viruses as random
assemblages of genes. "We have to confer to these guys a nobility, a
genealogy. Not only a genealogy. They are very ancestral, and their
ancestors are at least contemporary with ours and those of all
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