Are viruses alive?
Dale R. Worley
drw at zermelo.mit.edu
Mon Jul 20 14:10:13 EST 1992
In article <3935 at news.duke.edu> una at phy.duke.edu (Una Smith) writes:
Viruses are _not_ self-replicating. They are (we think) evolved
from self-replicating, living cells. In the course of evolution
viruses have discarded all but a very few genes, and now depend
on the host cells which harbor them to replicate the viral DNA
and build the viral coat proteins.
Viruses *are* self-replicating, in the right environment, just as we
need oxygen to be self-replicating. It's just that viruses require
other living things in the environment.
The crucial thing is that the virus genome replicates *independently*
of the genome of its prey. The reason that the various chromosomes
inside me are classed as all one living thing is that they
(more-or-less) have to replicate together, forcing them in to a
certain amount of altruism toward eachother, making them behave as a
coordinated system. The virus genome can replicate independently, and
so it doesn't act in a coordiated system with my genome.
In article <robison1.711564533 at husc9> robison1 at husc9.harvard.edu (Keith Robison) writes:
A friend and I recently got into this discussion. If viruses are
alive, are plasmids? Transposons?
That's a touch one, because they replicate in two different ways --
One is the spreading of copies throughout the organism they inhabit,
which is independent of the organism's main genome. The other is the
production of new organisms carrying the plasmid/whatever, which is
coordinated with the replication of the main genome.
Dale Worley Dept. of Math., MIT drw at math.mit.edu
Don't use humor in postings -- There is nothing you can say that is so absurd
that someone won't take it seriously, and then *complain about it*.
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