Plant Biotechnology and Genetics: Principles, Techniques and Applications

(Brent) #1

  1. Most regulatory bureaucracies assume that “traditional” means of genetic modifi-
    cation are risk-free, but that the processes of biotechnology inherently pose risk
    (Fig. 12.1). This assumption is rarely challenged, in spite of scientific studies over
    several years and from many countries establishing that the processes of biotechnology
    are not inherently more hazardous than other breeding methods [see, e.g. OECD (1986),
    NRC (1987, 2004), and Kessler and Economidis (2001)]. Of course, challenging the
    assumption opens the door to potential regulation for all products of plant breeding,
    not just those derived from rDNA. And since there is little or no public demand to
    launch risk assessments for conventional agriculture, the only scientifically valid pos-
    ition is to relax the strict regulation of at least some benign GMOs to the level of
    that imposed on conventional agricultural products of similar risk. In many parts of
    the world, relaxing regulatory oversight of GMOs is politically unpalatable, even if
    scientifically justified.

  2. A major motivation in some jurisdictions to regulate GMOs exclusively is the
    assumption that transferring genes across the species barrier is unnatural and potentially
    hazardous. However, the concept of a rigid species barrier is itself inherently flawed, as
    there are countless examples, both in nature and under human manipulation, of moving


Figure 12.1.Relative likelihood of unintended genetic effects associated with various methods of
plant genetic modification. The gray tails indicate the conclusions about the relative degree of the
range of potential unintended changes; the dark bars indicate the relative degree of genetic disruption
for each method. It is unlikely that all methods of genetic engineering, genetic modification, or con-
ventional breeding will have equal probability of resulting in unintended changes. Therefore, it is the
final product of a given modification, rather than the modification method or process, that is more
likely to result in an unintended adverse effect. For example, of the methods shown, a selection
from a homogenous population is least likely to express unintended effects, and the range of those
that do appear is quite limited. In contrast, induced mutagenesis is the most genetically disruptive
and, consequently, most likely to display unintended effects from the widest potential range of
phenotypic effects. [From National Research Council (NRC) (2004); used with permission.]


12.4. CONCLUSIONS 303
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