Re: NANFA-- Genetically Modified Corn and its effect on

Bruce Stallsmith (fundulus_at_hotmail.com)
Mon, 09 Sep 2002 22:05:22 -0400

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Many of the wild genes are still present as recessives, or they're expressed
through some form of epistasis (we're going into molecular lalaland
here...). For natural selection to work, you can lose 99.8% of a starting
population as successful breeders, and only those plants with some tendency
to survive will do so and leave descendants carrying the previously rare
traits. And we have the usual naturally recombinant chromosome tricks such
as synapsis so various genes are not only conserved but have new avenues of
expression.

The same general pattern is true of dogs. If you go to a city like Rome or
Athens (no, not Georgia!) with a large street-dog population, notice that
there's a distinct tendency for these dogs to all look roughly the same:
about medium size build, with short, somewhat curly, coarse fur, and short
pointed ears and a relatively short, broad snout. This seems to be the body
type best suited at least for life in an urban area. They reach this point
even though much of the original genetic contribution comes from various
breeds of dogs.

--Bruce Stallsmith
Huntsville, AL, US of A

>Seems to me that whether it could/would "revert" is dependent on whether
>the
>genetic pool of modern corn still retains the genes to allow that.
>Re-application of untempered natural selection will not resurrect the
>ancestral plant if the full spectrum of the original genes has been
>significantly abridged by 1000's of generations of selective breeding. I
>lack
>any hard facts to know whether it has or has not suffered such a loss, but
>it
>seems almost inevitable, given how long and industriously humans have been
>mucking with the genes of corn in particular, indirectly via artificial
>selection or more recently directly with what we think of as GM techniques.
>And while some of the lost original genes could conceivably be "replaced"
>by
>random mutation ... on a considerable time-scale ... mutation is equally
>likely (1) to create different expressions of genes that would "be
>successful"
>and cause the critter in question (corn in this case) to "veer off-course
>on
>its re-tracement path backwards through history to get back to its roots"
>(if
>that phrase makes any sense.)
>
>.02
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