The People's Seed Bank

Brian Sandle bsandle at shell.caverock.net.nz
Mon Dec 11 12:14:31 EST 2000


In nz.reg.canterbury.general Marty Sachs <msachs at uiuc.edu> wrote:
> In article <976502878.730794 at cobalt>, Brian Sandle 
> <bsandle at shell.caverock.net.nz> wrote:


>> In nz.reg.canterbury.general Marty Sachs <msachs at uiuc.edu> wrote:
>> > In article <976378882.461061 at cobalt>, Brian Sandle 
>> > <bsandle at shell.caverock.net.nz> wrote:

>> >>  Our data indicate that some stress(es) imposed by
>> >>    the transformation process, e.g. osmotic treatment, bombardment and
>> >>    selection, leads to cytological variation in transgenic oat plants, 
>> >>    an
>> >>    observation similar to that observed in our recent studies with
>> >>    transgenic barley plants. (C) 2000 Elsevier Science Ireland Ltd. 
>> >>    All
>> >>    rights reserved.
>> >> 
>> >> 
>> >> {And I should like to see the whole article, expaling that last bit
>> >> further, of course.
>> 
>> 
>> > OK, the proper control, to make your point, would have been cultured 
>> > plants bombarded and treated exactly the same way as the transgenic 
>> > plants, but without the DNA.
>> 
>> Do you, or anyone on the added newsgroup
>> bionet.molbio.methds-reagnts
>> know of any such controlled expts?


> I don't know of any off the top of my head.

It seems strange that such a fundamental question woudl not be more widely
followed.

How do you think they drew the conclusion:

    Our data indicate that some stress(es) imposed by
    the transformation process, e.g. osmotic treatment, bombardment and
    selection, leads to cytological variation in transgenic oat plants, 

without the test? Is `bombardment and selection' to include only the
damage less the effect of the new genes?

It almost seems a bit like a cover up.

>> 
>>   Going through cell culture is only one 
>> > aspect of stress generated variation.  The actual bombardment, osmotic 
>> > treatment, and selection techniques also contributes to the variation 
>> > the authors observed.  Technically, this 'extra' variation is not 
>> > 'somaclonal' in nature, but due to other stresses.
>> 
>> So what do you call it something different when tissue culture is not the
>> cause of it?


> The more general term would be 'stress induced' variation.

And do you include it under `stress induced' when the genes are entering
in such a manner as they later exit but leave a problem footprint?

>> 
>> 
>>  The non-transgenic 
>> > plants were simply derived from tissue culture without any of the other 
>> > treatments, most of the variation in these was somaclonal.  
>> 
>> > Indeed, methods developed to transform plants with as little stress as 
>> > possible would be preferable in that the less unwanted variation 
>> > introduced, the better.  However, all breeding methods introduce 
>> > unwanted variation that needs to be dealt with.
>> 
>> So the question is that if the biolistically, haphazardly, implanted 
>> genes 


> The genes introduced via biotech certainly aren't any more haphazardly 
> introduced than those via genetic wide-cross.

If that is true it may be a reason to increase safety measures there, too.


>> do not lead to extra variation (in some species more or less - that would
>> be a hint to the haphazardness of the process also) at the 5% level in 
>> the
>> short term, will there be any later effect in the tortuous programmed
>> pathways of evolution - say a Hox gene not showing its head until some
>> pest is present, or whatever?


> Certainly, no more so than genes introduced via a genetic wide-cross.  
> Also, probably no more chance of this than finding a desired trait,  
> that is caused a naturally mutated promotor, and using that in 
> conventional breeding.

I have the notion that wide cross is a bit more of key in lock sort of
thing whereas transgenics is more of a skeleton key or worse.

>> 
>>  >> >> The point is the extra instability of
>> the transgenic results.}
>> 
>> 
>> > Well, not exactly, the point is that the stresses introduced by the 
>> > procedure can cause more variation than tissue culture does by itself.  
>> 
>> Have to look at whether it is the same sort of distribution as may be
>> caused by promoters or enhancers starting to reside near genes
>> unaccustomed to them.


> Again, if this were a problem, this would also occur with genetic 
> wide-cross.

I feel that in wide cross that promoters are more likely to be transferred
in segments with more benign ends.

>> I think I have already answered most of that, but you admit improvement
>> would be useful, 


> Yes, I certainly agree that improvement in reducing unwanted variation 
> would be useful.  You should note that in this regard, present biotech 
> methods are a vast improvement over genetic wide-cross.

You mean that once you have gone through the long selection process that
transgenic is more stable than wide-cross?

>> and I claim that the precautionary principle should be
>> used more in the mean time. 


> IMHO, it is being used with biotech methods much more so than with other 
> breeding techniques.

The transgenic crops are very new but also are over 50% in use in
lots of USA. That scarcely seems precautionary.

Ten years is long in terms of current financially driven economics, but
short in terms of human generations.

>> Don't be basing the questions you ask on the
>> shifting sands of the current financially driven economics.

> I don't.






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