genetically engineered crops
cboake at utk.edu
Thu Oct 1 12:17:07 EST 1998
In article <VA.000015b8.0019c86f at rogersbox>, rgw at office-futures.com wrote:
> In article <360F7BB8.5FC0C79D at uga.cc.uga.edu>, Wayne Parrott wrote:
> > The target market was for chicken feed, not human consumption.
> And, of course, chickens have no connection with the human food chain.
> I'm afraid we in Britain have become more than a little sensitised to the
> "It's alright, the system works and we scientists have everything under
> control" type of utterance. Rightly or no, fairly or no, we are now deeply
> suspicious of any such pronouncements. Our 'take home message' has been
> rendered fragments of mad cows entering, and continuing to linger, in our
> daily diet and in the diet of things we eat.
Not all scientists show that much hubris. Two potential problems with
transgenic plants (i.e. plants that have had someone else's gene stuck in
with modern technology) are being investigated by scientists and there is
plenty of reason to be concerned. First, some of those crop plants (e.g.
the brassicas) can send their pollen to wild (frequently weedy) relatives,
and thus the genes for pesticide resistance can get into the pests (see N.
Ellstrand's research for examples). Second, although b.t. sounds like a
cool way to nail specific pests, insects are becoming resistant to it;
this has occurred with several pest species, the only study I can recall
is by B. Tabashnik. If an entire field of plants carries b.t. genes, it
will provide strong selection on the local insects that favors any
mutation that confers resistance. Some management schemes such as
interplanting b.t.-carriers and noncarriers may help to reduce the chance
of resistance arising; I don't know the status of research in that area
and I have a pretty strong suspicion that even if such recommendations
were made, they would be recommendations rather than requirements.
The problem isn't with the transgenic plants themselves, but with the ways
that they are used, and the lack of understanding of microevolutionary
processes by the people who promote and use them. The same processes
underlie the increasing number of types of resistance to insecticides,
and resistance to antibiotics.
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