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Re: Substantial equivalence - what is it?



Robert wrote:

> ... a central plank of GM food
> regulation appears to be "substantial equivalence" and so far I have not
> seen any strong defence of this term. In fact, so far, it appears to be
> pseudo science with no real substance.

SE is a term in the same field as "Objective", "thorough", or "to the
best of our abilities".  It is a guideline or at least a principle, but
NOT a procedure.  International food safety agencies hold it up as an
ideal which individual countries should subscribe to.  As a result
countries like Canada look at specific applications of the SE principle
formed by non-profit groups and other countries and then forms its own
practical definition of SE as a regulatory term.  Simply saying
something is SE doesn't really say much unless you are talking about a
specific countries ruling that something is SE.

...
> 1. New Scientist 8/May/1999 - Even with the right gene, you might not see
> green.
...
I may not be answering the question, but I think you are saying that
regulatory assessments do not consider the function of a new organism,
only the Genes within - regardless of their order.  I don't know about
the application of SE in other countries (I hear there are serious
problems with the US system) but in Canada, where I live, an organism
with the exact same genes is definitely NOT SE if the order (and
function) is changed.  Sequence has long been known to have a
fundamental role in genetic function.

... 
> 2. New Scientist 15/May/1999 - Fiendish Fungus, ...
...
> The above is an example of the problems that can be caused just by
> physically relocating organisms. Can we pedict the effect of gene transfer
> when we release "substantially equivalent" organisms ino the wild ?
...

It sounds like you are commenting on the general philosophy of scaling
future risks to match the level of risk that have existed naturally in
the past.  This is an important area for discussion in my opinion.  We
must consider the population, economic globalization, mass agriculture
and monocultures, and the prioritization of other human issues when we
form our opinions on whether the historical level of risk is still
acceptable in a new world.  My feel (so far, and for now...) is that we
need to accept the same risks that existed in the past and possibly
prepare better to react quicker and with more widespread research
commiserate with the population increase we are experiencing.

> 
> 3. BSE. ...               ...I imagine
> that in terms of "substantial equivalence" PrPc and PrPsc would be regared
> as totally equivalent....

Certainly NOT.  Not even in the USA! <wink>
Variances in protein expression are a direct result of variances in
DNA.  SE has to apply to every aspect of an organism, not just the DNA,
genes, Proteins, or function.  Substantial Equivalence does not just
apply to a physical substance in an organism; "Substantial" is used in
the sense of a more strict version of the word "Significant".   In
Canada (The only system I've studied in depth), Every variation in the
organism must be outlined as well as all possible effects of each
variation and all possible combinations of those variations and
effects.  The result is that only the most minor of changes in a plant
are approved through Substantial Equivalence.  If the regulations and
assessment techniques we have now were in place in the forties, I bet we
would not yet have many of the grains that came out of the Green
Revolution that are so widespread today.




Trevor Lien.