GMO Talks by Professor Elizabeth Vierling

University of Massachusetts Professor Elizabeth Vierling presented two talks on GMOs sponsored by the LWV Amherst, on April 15 and November 20, 2014. She noted that people are concerned about GMOs and stressed that knowledge-based processes should be used to understand the risks and rewards of new technologies. A brief summary is presented here. More information is available on her website.

What is a gene? A gene is a segment of DNA with a specific sequence of base pairs that encodes the information required to make a specific protein.

What is a genetically modified organism (GMO)? Genetic modification changes a plant’s DNA by inserting a gene or modified gene that will modify a specific protein in the plant.

What are the major genetic modifications in agricultural crops today?

  • Herbicide resistance: Inserted gene allows the plant to resist Monsanto’s herbicide ROUNDUP (glyphosate). Although not discussed in these talks, Prof. Vierling notes that the company Bayer has also produced plants resistant to another herbicide (glufosinate), and other plants are in development.
  • Insecticide: Bt gene inserted into crops kills insects that eat the plant. Bt refers to Bacillus thuringiensis, a common soil bacterium that produces a protein harmful to some insects. In order to kill the insect, the Bt protein must attach to a specific receptor found only in certain insects.
  • Other uses: About 80% of the Hawaiian papayas are genetically modified to resist ring spot virus. A gene from a pepper plant has been found and used to protect African bananas from wilt disease. However, there is a disease that is a serious threat to Florida’s citrus industry, called Citrus Greening. No resistance gene has been found in any edible citrus crop that can be used in conventional breeding to prevent this disease, although genes from other plants may prove suitable; research is continuing.

What are the major crops that are GMOs? GMO crop use began in 1996. Major GMO crops in the United States are corn, soybean, cotton, canola, sugar beet, alfalfa, papaya, and squash. Professor Vierling stated that currently there is no GMO wheat or rice in production. Today, about 90% of all the corn planted in the U.S. contains either herbicide resistance, insecticide provision, or (usually) both. Over 80% of soybeans are herbicide resistant, but there is no insect resistant soybean (no Bt soybean). Many other countries plant GMO crops, including Brazil, China, India (cotton only), Canada, and Argentina.

Are GMOs toxic to humans? No negative effects on human health have been found, according to the World Health Organization, American Medical Association, National Academy of Sciences, EPA, FDA, USDA, European Food Safety Authority, and other scientific organizations. Moreover, GMO crops containing Bt can greatly reduce the use of insecticides, a benefit to humans. Since the Bt protein must attach to a receptor found only in specific insects, it is digested harmlessly by humans.

Professor Vierling cautioned that “correlation is not causation”. Just because two trends in data are similar does not mean that one causes the other.

Do GMOs cause herbicide resistance? Professor Vierling presented a graph showing that herbicide resistance began about 20 years before GM crops were introduced. The herbicide resistance introduced to crops is specific to ROUNDUP, whereas weeds are becoming resistant to a broad range of herbicides. This provides evidence that GMOs did not cause the herbicide resistance. It is the overuse and misuse of herbicides that leads to resistance, which can occur on both GMO and non-GMO plants.

Where do we go from here?

Professor Vierling posed the question: Are GMOs the problem, or is the way “Big Agriculture” is practiced the problem? For example, four large companies, of which Monsanto is one, own 80% of the genetic modification intellectual property.

Three government agencies regulate GMO crops:

  • FDA: safe to eat?
  • EPA: safe for the environment?
  • USDA: safe to grow?

Is this adequate government oversight?

Professor Vierling concluded her talk by saying more money is needed for agricultural and basic plant research, noting that each gene, or trait, needs to be assessed separately.

Martha Hanner and Diana Stein

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