On Tue, 25 Jan 2000 11:52:38 -0500
"david gobel" <email@example.com>
writes, in his continuing "viruses" thread:
>Now for the REASON for the question...most research on viruses focus on the
>ideopatic/pathologically negative to humans action of viruses. What if there
>are massively useful but extraordinarily subtle benefits that viruses convey
>to humans about which we are totally ignorant. Is there any research on
>this? If no one is looking here, my intuition is that it would yield
You original post got me to thinking. My feeling is that all the bits and
pieces of the "ecocosm"--as you so aptly call it--play a range of roles,
both cooperative and competitive, so looking for the beneficial role for
viruses strikes me as a bit of good outside-the-box logic.
An online search found the following in Dartmouth's online Virology "text":
>Some scientists believe that
> viruses evolved out of cells,
> gradually losing so much of
> their genetic information that
> they became dependent on
> other cells for their
> reproduction, or alternatively
> that they arose from bits of
> genetic material within the
> cell that acquired a life of
> their own. Other scientists
> believe that viruses originated and evolved along
> with the most primitive forms of life, the simple
> molecules that gained self-replicating abilities.
> Some of these took the form of cells - others
> evolved into the viruses which parasitized those
> same cells.
> There are a number of complex molecular life
> forms that blur the boundaries [between] cells and viruses.
> There are pieces of self-replicating genetic
> material found in bacteria, called episomes,
> which evolve independently of their hosts, and
> can even move from [one] host to another - but carry
> genetic information that is beneficial or even
> essential to their host. Many bacteria would be
> unable to reproduce at all without them.
> Episomes are in many ways quite similar to
> viruses - except for the fact that they only
> reproduce themselves when their hosts do,
> whereas viruses reproduce themselves hundreds
> of times, causing disease.
>Viroids and virusoids are the smallest and
> simplest form of all recognized viruses and
> self-replicating molecules. Viroids are composed
> of nothing more than a single, circular strand of
> genetic material, and cause disease in plant cells.
> Replicating in the nuclei of plant cells, they often
> cause striking diseases in their host plants.
> Lacking even a protective shell of protein,
> viroids do not even spread easily from one cell
> or plant to another. Virusoids, like viroids, are
> small, circular molecules of genetic material.
> Virusoids "infect" other viruses, using the
> replication processes of the host virus to
> replicate themselves instead.
>From the 13 OCTOBER 1999 issue of EurekAlert I found the article
> New University of Georgia study indicates possible
> ancient origin for retroviruses, the class to which HIV
wherein I found the following:
> Retroviruses and related free-moving pieces of genetic material called
> retrotransposons are extremely important in the genetic makeup of
plants and animals,
> despite the fact they were not discovered until about 50 years ago.
For example, half
> of the maize genome is made up of retroelements, and in some plants
such as wheat
> and pine trees, 90 percent of the genome may be constructed around
> Researchers now believe that these "retroelements" are major causes of
> mutations and are significant factors in genome evolution. McDonald's
> several others are using the relatively new science of genomics to
study how these
> elements have changed plants and animals. By analyzing the sequences
> acids in certain genomes, they can better understand which
retroelements have been
> highly conserved through species and over time.
All of which suggests to me--if I may speculate somewhat brashly--that,
since a virus is fundamentally a dna transfer vehicle, it may have
originated during the early evolution of "proto"-bacteria as a
meta-reproduction strategy. Back when kt was an rna world, broadcasting
your rna, which then claims a place on the genome of "the other", is very
much in line with the selfish gene theory of evolution. However, looking
at this last sentence, "selfish" doesn't seem quite right, when everyone
is promiscuously shuffling bits of genetic material about, and "your rna"
seems equally questionable, when each individual is a one-off mish mash of
the various bits and pieces floating around.
Great question Dave. You're absolutely right. We've gotta get past the
virus-as-bad-guy prejudice, and start seeing them as
direct-to-your-pore-step (as in cell pore) delivery, courtesy of Feral
Of course the recombinant gene folks are already hip to this.
Best, Jeff Davis
"Everything's hard till you know how to do it."
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