Did you see the news article today about the genetic engineering of a certain
farm crop?  It turns out that the engineered gene, which makes the crop
resistant to herbicides, is now showing up in weeds adjacent to the crop.

Does this scare you?

11 responses total.

A weed is just an unwanted crop.  Yea, it's scared me for a long time
though.

Yes, I've been following that one pretty closely. The crop is rapeseed, which
has been commonly marketed as canola, because there are people who are
offended by its correct name, rapeseed.

The genetic engineering performed is to insert a gene into rapeseed which
confers immunity to a common herbicide (like what's in Scott's "Round-Up").
This herbicide is a lot less nasty in the environment than conventional 
herbicides, btw. It is limited in use, because it tends to kill all
vegetation.

By inserting this gene, rapeseed can be grown much more efficiently, as all
of the wild vegetation (weeds) can be controlled by a simple relatively
harmless chemical. This is true throughout the world.

The problem was encountered in the Northern US plains and Canada, which is
the only place in the world where there are weeds similar enough to rapeseed
to be able to interbreed. The result has been the spread of this gene into
the rapesedd-related weed population.

The solution is not to use this method of weed control in a rapeseed field
in North America. It is prudent to be concerned about these issues, but not
appropriate to be scared. This is not creating any kind of "super-weed" that
cannot be controlled or anything like that. The harm is mostly economic to
the people who are trying to use this kind of control. If they stop the spread
of the genetically controlled weeds, they will still be able to use the gene
in other crops, but if they foolishly continue to use it on rapeseed, they
will profilerate these resistant weeds, and spoil the benefit for all crops.

Thanks for the informative note on the subject.  It seems like there is enough
"trial and error" in this sort of thing, that no one can predict the outcome.
Accidents are bound to happen. 

I am curious how the gene could have spread.  By viral infection?

I think it occurs by mechanical transmission - just by the genetic
material of many plants being scrambled together by wind, weather,
insects, machines, etc.  I recall that one way transgenic plants are
created is to put the genetic material you want to try to add to a plant
upon fine gold dust, and *firing* this stuff at seeds. It is a "shotgun" 
approach, but enough of the carrier gold particles penetrate the seed
nuclei, that a few seeds arise carrying the new trait. I think they also
add some characteristic that can be easily identified at the same time in
order to pick out the plants that have been altered. 

I think if you tried to scramble plants together you would have dead plants.
The gold particles are a lot smaller than dust, and can penetrate the cell
membrane without destroying it.  If an insect took bites out of two plants,
the bit cells would probably die instead of mixing genes, but insects do
transmit plant viruses (as happened to my yellow raspberry, which acquired
crumbly berry disease).  I just wondered if your source had mentioned it.

From keesan@m-net.arbornet.org Sun Feb 15 23:38:39 1998
Date: Sun, 15 Feb 1998 23:17:13 -0500 (EST)
From: c keesan <keesan@m-net.arbornet.org>
To: keesan@grex.org
Subject: rapeseed

September 7, 1997
   
   4. There is evidence that GE rape cross breeds with wild relatives
   spreading its foreign genes. Rapeseed is known to spread beyond the
   fields it's planted in to wild relatives growing in our hedgerows. The
   GE variety carries bacterial genes and an antibiotic resistance gene.
   There are fears that such an antibiotic resistance gene could render
   bacteria immune to antibiotics.
                                      
   Area Press Officer Martin Hughes-Jones 01884-821164
   email : martin.hughes-jones@gexpress.gn.apc.org
   
        (Southwest Greens)

The answer was simpler than I thought, especially after I reread #2.  (close
enough to interbreed - they did interbreed.)

Ah yes...it was an antibiotic gene used to "tag" the transgenic seeds,
that I read about.

In coop 34 (new conferences) I suggested a conference on issues related to
genetics.  Is there enough interest?  Please comment in coop.  (And Rane, you
are the obvious candidate for a FW).

No, thanks. I'm interested in too many things for the time I have...
I'm inclined to think that a whole cf devoted to genetics is too narrow
a topic. It fits in well with science, and health, depending upon the
emphasis of an item.

Genes in bacteria often spread easily from one species to another, 
because when a bacterium dies, and spews its contents into the 
environment, other bacteria are able to accept small pieces of DNA 
directly from the environment, and incorporate them.

This happens primarily with plasmids, which are little rings of DNA, 
contain a small number of genes. But some very important genes are 
carried on plasmids, including those conferring resisitance to certain 
antibiotics. The growing problem of such resistance being acquired by 
dangerous bacteria can be traced in part to ordinary non-dangerous 
bacteria developing and maintaining resistance, and then this 
trans-species transfer. There are issues here that are off-topic, like 
how to avoid selecting for an maintaining resistant strains. In fact, 
transfer like this is not something you find most plants doing, so it 
may all be a technical digression of academic interest only. 
(my specialty)

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