Food Safety - The Oxford Topic of Food, Politics, and Society - page 591

there is no species barrier for genes. A small piece of DNA that encodes the selected gene
is inserted by transformation into the target plant and transformed cells of that plant are
regenerated into whole plants containing the desired gene. Additional DNA fragments
may be combined with it to form an rDNA molecule. A means to select transformants
is required for this scheme to succeed. Antibiotic resistance genes isolated from bacte-
ria were originally used as markers for transformed cells, and became one element of
political critiques of biotechnology. However, other methods have superseded the use of
resistance genes or depend on their removal after selection thus ending polemics about
the safety of antibiotic resistance genes in transgenic plants. It is, however, worth noting
that risk assessors long ago concluded these genes were safe to use (Ramessar et al., 2007;
Chassy, 2010). Candidate plants are then characterized and are eventually crossed with
commercial varieties to produce transgenic varieties carrying the newly introduced
trait. The in vitro rDNA techniques of modern biotechnology have been used to produce
new varieties with traits that could not be achieved by conventional breeding. The pro-
cess can also reduce the time required to develop a new variety. From a safety assessor's
perspective, varieties produced in this manner are more amenable to safety assessment
since the sequence and encoded genetic content of the inserted DNA is known a priori .
What's a GM Crop? A Revealing Truth
and New Challenges
Most countries regulate what they have chosen to call GM or GMO plants, foods, and
feeds. The exact legal definition of these terms, which differs from country to country,
will have an impact on the regulation of new technologies whose products are appear-
ing on regulators' desks or those that are under development. Differences in definition
can result in a product being classified as a GMO in one country and not in others. For
example, EU directives define a GMO as an “organism, with the exception of human
beings, in which the genetic material has been altered in a way that does not occur natu-
rally by mating and/or natural recombination.” The intent of this definition obviously
endorses all food that is natural and captures food that is changed in some way through
human intervention. Since virtually all food would be classified GMO under this defini-
tion, the directives also exclude a number of categories including organisms produced
through in vitro mutagenesis and even organisms into which genes isolated from unre-
lated organisms have been inserted. In the EU, a product that contains >1% by weight of
a highly purified soybean oil isolated from GM soybeans, highly purified starch from
GM corn, or highly purified sugar isolated from GM sugarcane or sugar beets, must be
labeled as containing GM even though no trace of the GM plant, or inserted DNA and/
or proteins, can be found in the highly purified products. Ironically, a cheese prepared
with a transgenic bacterium, or wine or beer fermented with transgenic yeast, does
not require a label indicating that it contains GM ingredients, although billions of live