GMO Myths and Truths

Further rigorous testing is not required, so
unexpected changes in the GM crop are unlikely
to be identified. Also, testing for interactions
between the genome of the GM crop and the
environment is not required.
However, the degree of similarity that a GM
plant needs to have to non-GM counterparts in
order to pass this comparative safety assessment
has never been defined. A comparative assessment
of a GM plant often reveals significant differences
in its composition that are outside the ranges
of other non-GM varieties, including historical
varieties. But even in these extreme cases,
according to scientists who have served on
regulatory bodies, the differences are often
dismissed as “biologically irrelevant” (see 3.1.2). 52
Independent scientists have heavily criticised
substantial equivalence and comparative safety
assessment as the basis of safety assessments of
GM crops. 6,16,52,55
2.1.7. Weakening comparative
assessment further by widening the
range of comparison
The comparative safety assessment is itself a
flawed basis for assessing GMO safety. Yet recent
developments have further weakened this already
inadequate method.
An EU Directive on the deliberate release of
GMOs requires that the comparator against which
the GMO should be assessed for safety should
be “the non-modified organism from which it is
derived”. 56 The EU regulation on GM food and feed
agrees that the comparator should be the non-GM
counterpart. 57
These rules ensure that the GM crop or food is
compared with its genetically similar (isogenic)
non-GM counterpart. The comparator will have
the same genetic background, but without the GM
transformation. So the comparison is correctly
designed to find changes caused by the genetic
modification process – which should be the
purpose of a GMO safety assessment.
Historically, EFSA has followed this principle
in its Guidances and Opinions. Yet in a Guidance
published in late 2011, EFSA departed from its
past practice and EU legislative requirements and
broadened the range of acceptable comparators.
EFSA even proposed to allow the use of GM
plants, rather than the usual non-GM isogenic
line, as comparators for stacked events (crops
containing multiple GM traits) and concluded
that in some cases plants from different species
might be accepted as comparators. 58 EFSA’s new
approach is in line with industry’s practices. 50,51
But whether it complies with EU legislation is
questionable.
More importantly, the approach of comparing
a GM crop with unrelated or distantly related
varieties grown at different times and in
different locations is scientifically flawed. In
order to determine any unintended disruption
to gene structure and function and consequent
biochemical composition brought about by the GM
transformation process, the only valid comparator
is the non-GM isogenic line, when the two have
been grown side-by-side at the same time. This
serves to minimize variables external to the GM
transformation process. Thus any changes seen
are likely to be caused by the GM process and not
some other factor. In contrast, comparisons with
unrelated or distantly related varieties grown at
different times and in different locations introduce
and increase external variables and serve to
mask rather than highlight the effects of the GM
transformation.
In parallel with the trend of widening the range
of comparison in the comparative assessment of a
GM plant’s composition, industry and regulators
have adopted a similar scientifically invalid
approach to assessing the health effects of a
GMO in animal feeding trials. In these cases, they
dismiss statistically significant changes seen in the
animals fed the GMO as compared with those fed
a non-GM diet as “not biologically meaningful”
or “within the range of biological variation”
(see 3.1.2–3.1.4 for a detailed discussion of this
practice and how it places public health at risk).
These practices run counter to good scientific
method and could be described as a way of
“disappearing” inconvenient findings of the
experiment in question by bringing in data from
other experiments until the convenient answer
(that the GMO is no different from its non-GM
counterpart) is reached.
GMO Myths and Truths 28