Geneticaly-Modified Foods (GMFs)
The First Whole Food: FlavrSavr
Tomato
Also in the spring of 1994, Calgene's
FlavrSavr tomato entered the final stages of FDA review. FlavrSavr was
the first whole food from plants reviewed under the policy issued by the
FDA in May 1992.
In the debate whether regulation
should be based on "the product or the process," the FDA decided
to continue to base its judgments on the product. The policy assessed
new foods from all genetically modified plants based on the expected
characteristics of the food and the genetic makeup of plant used to produce
the food, including any introduced genes, regardless of the genetic techniques
used to introduce the gene. Thus, the mere use of rDNA techniques would
not trigger any unique regulations. Nor did FDA require special labeling
of foods developed using recombinant DNA techniques.
The policy included special provisions
to safeguard against the potential transfer of an allergen from one food
plant to another. For example, a company producing a tomato containing
a peanut gene would have show the tomato does not cause an allergic reaction
in people known to be allergic to peanut.
Calgene, headquartered in Davis,
California, developed a tomato that remained firm even as it turned red
and tasty as it ripened.
Researchers inserted two genes linked
in tandem. One gene was a tomato gene modified to keep the tomato firm.
The other gene was a tag, a "selectable marker" that enabled the researchers
to find which plants received the two linked genes. Scientists had originally
found the gene in bacteria in nature, so the use of the gene in tomato
did not introduce a new gene to nature.
In January 1993, Calgene asked the
FDA for a two-track review. Calgene asked that the tomato itself be reviewed
under the May 1992 policy; and it asked for a review as a food additive
of the "selectable marker" gene and its protein. Calgene's decision to
submit the selectable marker gene and its protein to stringent review as
a food additive was the most cautious approach to approval. It was also
the most expensive approach, and one intended to maximize consumer confidence
in a pioneering product. Some observers expressed concern, however, that
Calgene's approach might set a precedent that the government would expect
or oblige other companies to follow.
On May 18, 1994, the FDA reached
two conclusions: 1) the modified plant is a tomato and is as safe as other
tomatoes, and 2) the selectable marker gene and its protein product are
safe and effective. The addition of the selectable marker gene originally
found in bacteria and the presence of the protein from the selectable marker
gene did not constitute either a significant change in composition or an
adulteration. Nor did the genetic manipulations cause any unintended change
in nutrient composition, and the company had satisfied the industry standard
of care in looking for such a change. Furthermore, as expected the FDA
did not require Calgene to include a label stating that the tomato was
modified by recombinant DNA techniques. Lastly, since the tomato is a whole
food, and since the FDA does not require ingredient labels on whole foods,
the agency did not require the company to include a label listing the selectable
marker gene and its protein products as a food additive.
Virus-resistant
Freedom II Summer Squash
Late in 1995 the USDA cleared for
commercial use a squash resistant to two types of virus. Developed by Asgrow
seed company of Kalamazoo, Michigan, the squash is remarkable in containing
three genes instead of just two: a selectable marker, and one gene each
from the two similar but distinct viruses. Because of the use of plant
virus genes, the squash was the first time that the USDA, rather than the
FDA, was the lead regulatory agency based on authority given in the Plant
Pest Act.
Farmers try to control the virus
diseases and the aphids that spread them by spraying their crops with insecticides.
Breeders have had difficulty developing aphid-resistant plants as well
as virus-resistant plants using genes from wild and cultivated relatives
of squash.
Recombinant DNA techniques enlarged
the breeders' gene pool. Work started in the laboratory in 1986 to find,
copy and move the genes into greenhouse plants. No longer limited to squash
for sources of resistance, researchers inserted into plant's chromosomes
a copy of gene from each virus to make plants resist the virus. They also
used the same "selectable marker" or "tag gene" used by Calgene to find
plants in which the three linked genes inserted successfully.
Beginning in 1990 Asgrow tested the
squash in field trials every growing season. Asgrow formally petitioned
the USDA in 1992 to declare the squash a "non-regulated article," providing
the clearance needed to commercialize the squash. The petitioning process
requires the USDA to announce in the Federal Register the company's request
for "non-regulated article" status. Any interested person can then submit
comments for a period after the announcement is published.
USDA sent Asgrow's petition through
three rounds of comment. USDA in response to each round of comments asked
Asgrow for more analysis. USDA was at first concerned with molecular aspects.
Later USDA expressed concerns about weediness, spread of the resistance
gene by pollen, and possible acceleration of new strains of the virus.
After reviewing Asgrow's additional analyses, USDA declared in late 1994
the squash and any hybrids developed from it to be "non-regulated articles."
New Leaf
Potato
A common soil bacterium named
Bacillus thuringiensis produces a protein toxic to many plant-eating
pests but harmless to beneficial insects such as honeybees as well as to
humans. "Bt" is available
as a commercial pesticide registered by the EPA. When dusted on potato
plants, a specific strain of Bt kills Colorado potato beetle. The
dust is effective for only two to three days.
In the mid 1980's several companies,
including Agracetus, Agrigenetics (now part of Mycogen) and Monsanto, transferred
a copy of the Bt gene into plants. The goal was to produce plants
resisted insects by producing the Bt protein.
The EPA has been the lead regulatory
agency reviewing these plants. On May 5, 1995, the EPA announced the registration
of Monsanto's "NewLeaf" potato, making it the first registration
of a "plant-pesticide." This action cleared NewLeaf potatoes, a type of
Russett Burbank potato, for commercial production in 1995. The government
required no special label or segregation of Bt potatoes. The USDA
had also previously de-regulated Monsanto's variety.
Material taken from http://www.biotechknowledge.com