Agriculture Reference
In-Depth Information
In contrast to conventional breeding techniques, genetic engineering
allows insertion into the plant genome of single genes coding for new
traits such as herbicide or insect resistance. In addition to the introduc-
tion of the intended new characteristics, unintended effects may also
occur. Similar to traditional breeding techniques, unintended effects
could potentially be caused by genetic rearrangements or metabolic per-
turbations. There is no indication that such unintended effects are more
likely to occur in GM crops than in conventionally bred crops.
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Yet, the
introduction of GM crops requires a pre-market safety assessment that
includes not only a characterization of the novel genes and gene prod-
ucts but also an array of analyses with regard to any unintended effects
that may be evident in the phenotype or the chemical composition of the
GM plant when grown under the same conditions as the nonmodified
controls.
MolecularCharacterization
Genetic engineering does not only provide tools for the construction of
GMO but also for the analysis of the inserted DNA sequences and its
flanking regions in the plant genome to determine whether rearrange-
ments of the transgene construct or the insertion site have occurred and
whether endogenous genes might have been disrupted or open read-
ing frames have been created through the insertion. The amino acid
sequences deduced from any open reading frames are to be compared
to known sequences of allergens and toxicants. If fusion proteins are
expressed, these would undergo the same safety assessment as intention-
ally introduced new proteins.
ComparativeAnalyses
Different from conventionally bred crops, GM plants are subjected to
thorough analyses not only of their genetic but also phenotypic and
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Cellini, F. et al. 2004. Unintended effects and their detection in genetically modified
crops. Food and Chemical Toxicology 42(7): 1089-1125.
