Re: corn pollen (was Beginning of end...)

Lon J. Rombough (lonrom@hevanet.com)
Mon, 10 May 1999 06:14:29 -0700

I know what you mean about unexpected results from transgenic material, or
even hybrids between distant relatives done the "traditional" way. I've
seen hybrids between two species that produced apomictic forms where there
hadn't been apomixis before. There are too many unknowns in how new genetic
material inserted into an old genome will react to say it's "safe" without
even the simple expedient of growing out the material for a good number of
generations just to be sure nothing new comes up.
In any case, I'll let others carry on the discussion - I was mainly
contributing one or two thoughts and haven't time to get into a long
discussion from here.
-Lon
----------
>From: "E. Ann Clark, Associate Professor" <ACLARK@plant.uoguelph.ca>
>To: sanet-mg@shasta.ces.ncsu.edu
>Subject: Re: corn pollen (was Beginning of end...)
>Date: Mon, May 10, 1999, 4:50 AM
>

>Lon:
>
>> movement. But then I don't know what kind of contamination levels would be
>> acceptible. In a big field, a hundred pollen grains in the wrong place
>
>Evidence is already available to suggest that this is a problem of
>commercial magnitude, and it can only get worse as mainstream
>grocery stores take up the non-GMO mantle and testing for GMO
>contamination becomes more commonplace and sophisticated. Consider
>the plight of the Texas farmer, who as i understand the story, had
>grown corn organically, processed it into tortilla chips
>and sent them off to Europe. They were found to have been
>contaminated, reportedly by genetic pollution according to the
>farmer, and sent back - at enormous cost to the farmer.
>
>
>> might multiply into some serious contamination if seed were being saved and
>> the contaminated types were inadvertantly selected. Of if only a very small
>> amount of contaminated grains were needed to throw off tests for BT toxins,
>> or the like. Seems like it wouldn't be hard to do a fast test (fast meaning
>> in a few months) by planting a field of something with an innocuous, but
>> obvious marker such as colored kernals next to a field of non-colored corn.
>
>This may, or may not, be a suitable test - and either way, the fact
>that we are having this discussion at all is a clear indication of
>"technology before science" mentality. As is the case with the Bt
>resistance problem (see latest issue of Science), companies were in
>such a rush to make a buck, that they rammed through a technology
>that is nothing if not externalizing of risk, without an adequate
>grounding in science.
>
>We don't know the pollination distances with certainty, although
>they are known to be in km rather than meters for field-scale canola,
>corn, and potato (I cite quite a lot of these figures, with
>references, in a recent paper given to the Toronto Biotechnology
>Initiative, a pro-biotech lobby group - see my homepage. We don't
>know much of anything about allelic frequencies, dominance:recessive
>relations, or many of the key parameters in the Bt resistance
>question. Check out 1998 or 1999 refereed publications on the
>subject, and you will be astounded at the degree to which they still -
> even today - are based on assumptions in the absence of evidence.
>
>The idea you propose may work, but it may not be generalizable because
>individual GE events can affect such critical processes as %
>outcrossing. See Bergelson et al., 1998 on the effect of putting an
>herbicide resistance gene into Arabadopsis - a selfing species -
>which turned some transgenic lines into 10% outcrossers. Outcrossing
>has nothing to do with herbicide resistance, but is illustrative of
>the general phenomenon of unintentional side effects caused by the
>process of breaching the carefully modulated integrity of both species
>and chromosome.
>
>Recall that, contrary to the hype, GE is far from "precise".
>Regardless of the method used, transgenes are inserted at random -
>unreliably, unpredictably, and unrepeatably. According to my breeder
>colleagues, there is still no method of knowing in advance where in a
>given chromosome, or even on which chromosome, a presumptive
>transgene will land. And, as I argue in a talk given on the weekend
>(The Faulty Assumptions of Field Crop GE, hopefully to be mounted on
>my homepage within a week or two), "order is everything". It makes a
>difference where on a chromosome, and on which chromosome, a
>transgene lands, because genes interact. Arguably, the genes
>themselves do not matter so much as where they are on the
>chromosomes. Interaction is everything. This explains, in large
>part, why unintentional traits - such as outcrossing - can be
>affected by GE. See Mae-Wan Ho's most helpful book Genetic
>Engineering: Dream or Nightmare (1998).
>
>What this means, is that pollination distances would have to be
>tested for each commercial GE event - not generalized over the whole
>species. Or, a worst case scenario would have to be adopted which
>would wreck havoc on production and commerce. And keep in mind, we
>are still thinking here on sexual outcrossing, without even
>introducing the risk of horizontal gene transfer. Ann
>
>
>
>ACLARK@plant.uoguelph.ca
>Dr. E. Ann Clark
>Associate Professor
>Crop Science
>University of Guelph
>Guelph, ON N1G 2W1
>Phone: 519-824-4120 Ext. 2508
>FAX: 519 763-8933
>http://www.oac.uoguelph.ca/www/CRSC/faculty/eac.htm
>
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