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Re: Evolutionary Theory



JSeward123@aol.com wrote:
> 
> My high-school biology teacher (who hates creation) taught us that 99.9999...%
> of all mutations are destructive and don't get passed on in future
> generations. So I fail to see how random mutations could result in something
> better. Even if there was a beneficial mutation, would it get passed on to its
> offspring in future generations?
> 
> JMHO,
> Jim

I suspect that mutation is cumulative. Most genes are introns that
don't seem to have any effect on the phenotype (at least none that
we can see, then again scientists have a history of being wrong
most of the time). In which case introns can mutate merrily for
generations and theoretically have no great impact on the population.
But occasionally I suspect that a mutation in an intron can
convert it into something useful (extrons, I think). Mutation is
a funny thing. I've heard that the gene that allows adult humans
to become lactose tolerant was originally a gene for doing something
else entirely (can't remember what), and that a few mutations here
and there happened to luck out and convert it into not only something
else, but something actually useful. Anything that gives a species
an edge, no matter how small, tends to become amplified with time.
The case is similar with sickle cell enemia and GDP6 deficiency.
Although they are detrimental health wise they give an immunity
to malaria, so it's no surprise that the two conditions are wide spread
in some parts of Africa.
        The point is (there was a point?) that perhaps we shouldn't
hang all of evolution on single mutations, but rather a series of
mutations over many generations that pave the way for successful
mutations. Changes in the phenotype may still be relatively sudden,
but perhaps introns had been merrily mutating for generations behind
the scenes.
        Wow, that was at least 4 cents worth.
-- 
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        Dann Pigdon
        Melbourne, Australia

        Dinosaur Reconstructions:
        http://www.geocities.com/capecanaveral/4459/
        Australian Dinosaurs:
        http://www.alphalink.com.au/~dannj
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