
April 5, 2000
WASHINGTON -- Even given the strengths of the U.S. system governing
transgenic plants, regulatory agencies should do a better job of
coordinating their work and expanding public access to the process as the
volume and mix of these types of plants on the market increase, says a new
report from the National Academies' National Research Council. The committee
that wrote the report emphasized it was not aware of any evidence suggesting
foods on the market today are unsafe to eat as a result of genetic
modification. And it said that no strict distinction exists between the
health and environmental risks posed by plants genetically engineered
through modern molecular techniques and those modified by conventional
breeding practices.
The committee called on the U.S. Environmental Protection Agency (EPA), U.S.
Department of Agriculture (USDA), and Food and Drug Administration (FDA) to
quickly come to an agreement on each agency's role in regulating plants that
have been genetically modified to resist pests. It also said that any new
rules should be flexible so they can easily be updated to reflect improved
scientific understanding.
"Public acceptance of these foods ultimately depends on the credibility of
the testing and regulatory process," said committee chair Perry Adkisson,
chancellor emeritus and distinguished professor emeritus, Texas A&M
University, College Station. "The federal agencies responsible for
regulating transgenic plants have generally done a good job, but given the
current level of public concern and following our review of the data, it is
the committee's belief that the agencies must bolster the mechanisms they
use to protect human health and the environment. However, I must also
emphasize that we believe it is the properties of a genetically modified
plant -- not the process by which it was produced -- that should be the
focus of risk assessments."
As the volume of transgenic products increases, more research will be
needed to examine and better detect their effects on human health and the
environment so that the agencies will have a more refined scientific basis
for making decisions, the committee said.
IMPROVING PEST RESISTANCE
Farmers have been trying to minimize their losses from crop pests for
hundreds of years by using conventional breeding practices, such as
hybridization, to develop crops with desirable traits. Some types of worms
cause an estimated $7 billion in crop losses per year in the United States;
the damage from insects is even more severe. In the past two decades,
scientists have used the tools of advanced molecular biology to more
precisely alter plants to be pest resistant.
Scientists use these methods to introduce genes that endow plants with
pesticidal traits, creating what are known as transgenic pest-protected
plants.
These genes may come from similar, sexually compatible species or from
completely unrelated organisms. Transgenic plants have been grown
commercially since 1995, and their use has increased dramatically since
then. In 1999 alone, more than 70 million acres of transgenic crops were
planted in the United States.
But some scientists and members of the public have expressed concern that
the genetic engineering of plants could result in unsafe foods, do
irreparable
harm to beneficial organisms, and spur the uncontrollable growth of weeds.
Given the dramatic increase in commercial planting of genetically engineered
crops and the safety concerns they raise, the Research Council decided to
initiate a review of the scientific data on potential health and
environmental risks and the use of this data in the regulatory process.
HEALTH-RELATED CONCERNS
Thus far, only in very rare circumstances have pest-protected plants caused
obvious health or environmental problems. For example, although a human
allergic reaction to a new gene product has never been documented for a
commercially available transgenic pest-protected plant, one such incident
did
occur at the research stage. In that study, people with a known allergic
reaction to Brazil nuts experienced a similar reaction when they were
exposed in skin-prick tests to soybeans containing a gene transferred from
the Brazil nut.
Priority should be given to developing improved methods for identifying
potential allergens, specifically focusing on new tests relevant to the
human
immune system and on more reliable animal models, the committee said.
Changes in plant physiology and biochemistry should be monitored during the
development of pest-protected plants. And because the potential exists for
transgenic plants to have increased levels of toxic plant compounds, EPA,
USDA, and FDA should create a coordinated database that lists information
about natural plant compounds of dietary or toxicological concern, to aid
researchers who monitor concentrations of these compounds in such plants.
ENVIRONMENTAL CONCERNS
In examining ecological concerns, the committee looked at the possibility
that transgenic plants could affect organisms which are not the target of
the
pesticidal trait, the potential transfer of novel genes from one type of
plant to another, and the evolution of new strains of immune pests.
Both conventional and transgenic pest-protected crops could impact so-called
nontarget species, such as beneficial insects, but that impact is likely
to be smaller than that from chemical pesticides, the committee said. In
fact,
when used in place of chemical pesticides, pest-protected crops could lead
to
greater biodiversity in some geographical areas. The committee called for
more research to examine these issues.
The highly publicized report of monarch butterflies being poisoned by pollen
from genetically engineered corn is an example of an issue that needs to be
researched further and will require rigorous field evaluations, the
committee
said. In that particular report, researchers showed that pollen from corn
which had been genetically engineered to produce Bacillus thuringiensis (Bt)
toxins -- a type of insecticide -- slowed the growth, and sometimes killed,
monarch caterpillars when enough pollen was placed on milkweed leaves fed to
them in a laboratory. Follow-up studies are needed in the field where pollen
density might be lower and the toxin might be deactivated by environmental
factors.
Concern also surrounds the possibility that genes for resisting pests
might be exchanged among cultivated crops and their weedy relatives,
potentially exacerbating weed problems -- a high-cost nuisance for farmers
and potential threat to the ecosystem. The committee recommended further
research to identify plants with weedy relatives, to assess rates at which
pest-resistance genes might spread, and to develop techniques that decrease
this likelihood.
Another ecological concern is the potential for pests to evolve and develop
a
resistance to plants that have been genetically modified to kill them. The
committee concluded that the ability of pests to adapt and develop
resistance
should continue to be evaluated. Such an occurrence could have a number of
potential environmental and health consequences, including a return to the
use of more harmful chemical pesticides. Strategies to manage the
development of resistance in pests should be encouraged for all uses of a
pesticide, be it in a spray form or produced by a plant.
IMPROVING THE REGULATORY FRAMEWORK
To improve coordination, EPA, USDA, and FDA should develop a memorandum of
understanding for regulating transgenic pest-protected plants that
identifies regulatory issues within the purview of each agency as well as
issues for which more than one agency has responsibility, the committee
said. The memorandum also should establish a process to ensure appropriate
and timely exchange of information between agencies. For 14 years, the
agencies have formulated policies for genetically modified foods under
guidelines set forth in the 1986 Coordinated Framework for the Regulation of
Biotechnology. The framework gives
each agency a role in setting safety standards based on legal
jurisdictions at the time. But the committee said the scope of each agency's
oversight needs to be clarified, especially when a new product is to be
reviewed by more than one agency.
Additionally, the committee took issue with exemptions in EPA's proposed
1994 rule for regulating certain transgenic pest-protected plants. EPA
proposes to grant categorical exemptions for all plants that have been given
a new gene from a sexually compatible plant, and for plants expressing
proteins that are derived from a virus, known as viral-coat proteins. But in
the first instance, the committee said that in some cases the transfer and
manipulation of genes between sexually compatible plants could potentially
increase human and environmental exposure to high levels of toxins.
Secondly, while plants with viral-coat proteins may be safe to eat, there
are environmental issues to consider because of their potential to
crossbreed with weedy relatives. The committee urged EPA to reconsider its
plans to grant categorical exemptions for these transgenic plants.
The committee also recommended that the agencies monitor ecological
impacts of pest-protected crops on a long-term basis to ensure the detection
of problems that may not have been predicted from tests conducted during the
registration and approval process.
A more open and accessible regulatory process is needed to aid the public in
understanding the benefits and risks associated with transgenic
pest-protected plants, the committee concluded. To increase access to the
process, existing Web sites for the coordinated framework should be expanded
to include more detailed information and to link all of the agencies'
decisions for any particular product.
The committee's work was funded by the National Research Council, which is
the principal operating arm of the National Academy of Sciences and the
National Academy of Engineering. The three, along with the Institute of
Medicine, constitute the National Academies. They are private, nonprofit
institutions that provide science, technology, and health policy advice
under a congressional charter. A committee roster follows.
NATIONAL RESEARCH COUNCIL
PERRY ADKISSON* (CHAIR)
STANLEY ABRAMSON
STEPHEN BAENZIGER
FRED BETZ
JAMES CARRINGTON
REBECCA GOLDBURG
FRED GOULD
ERNEST HODGSON
TOBI JONES
MORRIS LEVIN
ERIK LICHTENBERG
ALLISON SNOW
RESEARCH COUNCIL STAFF ** NOTICE: In accordance with Title 17 U.S.C. Section 107, this material is distributed for research and educational purposes only. ** |
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Last Updated on 4/8/00 By Rachel C. Benbrook Email: karen@biotech-info.net |
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