From: Bill Spight (bspight@pacbell.net)
Date: Wed 04 May 2005 - 14:29:34 GMT
All:
I have recently begun reading "The Great Influenza", by John Barry, 
about the 1918 epidemic. It's a good read. :-)
He says something about the evolution of the influenza virus that is 
probably old hat to many here, but was new to me. First:
"The more advanced the organism, however, the more mechanisms exist to 
prevent mutations. A person mutates at a much slower rate than bacteria, 
bacteria mutate at a much slower rate than a virus -- and a DNA virus 
mutates at a much slower rate than an RNA virus."
So far, so good. Nothing new. Next:
"Viruses that use RNA to carry their genetic information mutate much 
faster -- from 10,000 to 1 million times faster -- than any DNA virus."
Wow! Now:
"Different RNA viruses mutate at different rates as well. A few mutate 
so rapidly that virologists consider them not so much a population of 
copies of the same virus as what they call a 'quasi species' or a 
'mutant swarm'."
Needless to say, the influenza virus falls in this category.
There is a concern among memeticists and critics of memetics about 
copying fidelity. Some critics say that memes mutate too quickly to be 
true evolutionary entities, and some memeticists wish to restrict memes 
to entities with high copying fidelity.
Doesn't the example of mutant swarms allay those concerns? The flu 
virus, HIV, and others seem to mutate much, much more rapidly than 
memes, even accounting for their more rapid replication rate. Memes may 
mutate too rapidly to be analogous to species, but surely not too 
rapidly to be analogous to quasi species.
Comments?
Thanks,
Bill
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