Food from genetically engineered crops. Should we worry? Maarten J. Chrispeels
Genetic change resulting from crop domestication took 10,000 years. Teosinte (top) and corn or maize (bottom)
The March of Genetic Technology 1860Mendel: making crosses, introducing genes 1920Discovery of hybrid vigor 1950Inducing mutations 1960Tissue culture and embryo rescue 1980Plant transformation and GMOs 2000Genomics
Crop improvement has allowed food production to keep up with phenomenal population growth for the past 100 years.
The scientific basis of all crop improvement is the identification of the genes that encode certain phenotypic characteristics. Those genes can now be transferred more easily (via marker assisted breeding - no GM) or directly (through genetic engineering - GM)
Molecular agriculture makes new gene combinations possible Peas (on the left) that make a genetically engineered bean protein are insect-resistant and do not need to be sprayed with pesticides.
Creation of a GM plant relies on a natural gene transfer mechanism
What are people’s concerns Is this food safe? Should food be labeled? Are there adverse environmental effects? Patenting of seeds Discrimination against the poor Who benefits? All of these concerns apply to food and agriculture in general
These concerns are generally true for all innovations. Governments create policies based on the following principles: Promote the general welfare Maintain people’s rights (individuals, groups, corporations) Ensure justice: burdens and benefits must be fairly shared
Agriculture is the main cause of environmental change and degradation
Fires burning in Northeast Brazil’s Maranhao region Agriculture requires land clearing
Worldwide, 40 % of our food production depends on irrigation. Depletion of aquifers is occurring at twice the re-charge rate. Salinization is a major consequence of irrigation
Agriculture has narrowed the gene pool and caused a loss of biodiversity Wild Progenitors and Relatives Land Races Elite Lines
Environmental Hazards from Pesticides Substantial health impacts on workers Pollution of natural ecosystems/ waterways Loss of insect biodiversity in agroecosystems Creation of secondary pests Creation of insect races resistant to pesticides
Genetics is always better than chemicals: GM Cotton with a Bacillus thuringiensis Cry gene is resistant to Cotton Bollworm. Cry encodes an insecticidal protein
Some GM crops have the potential to mitigate the environmental impact of agriculture: less pesticide, less dust, more biodegradable herbicides “Roundup” tolerant soybeans can be Planted with no-till procedures, which eliminate plowing (dust), Save water and use a biodegradable herbicide herbicide
Hmm… I wonder if there could be gene flow? Gene flow occurs when crops cross with wild relatives growing in relative close proximity to the fields. Gene flow requires sexual compatibility Gene persistence requires an evolutionary advantage for the new trait
What are the main food issues in the US? The # 1 safety issue is bacteria (6000 deaths per yr.) The # 1 health issues are fat, sugar and salt
Are GM foods safe and nutritious? 1.All GM foods have been extensively tested and they are as safe as other foods in the market place. 2.GM crops can be made into convenience and “junk” food just like organic crops and other crops! 3.Nutrition depends on the food, not the method of crop breeding
Every year 250,000 children become blind because of vitamin A deficiency
Some GM crops will improve the nutritional quality of foods. Such foods are now in the pipeline.
A GM soybean line, developed as a collaboration between the USDA and DuPont, is hypoallergenic in humans. The approach is to down regulate the expression of the gene encoding the major allergenic protein (antisense)
Labels are not neutral! Produced by Radiation Breeding!
There are no GM apples anywhere! Is food labeled this way nutritious? Truthful labels can be misleading or meaningless
How to Label? Conventionally grownGMO Pesticides, twice a weekPesticide free
Should foods from GM crops be labeled? Perhaps! The US takes the view that if foods are “substantially equivalent”, the method of producing them need not be on the label. Farmers use a variety of techniques, and keeping production streams separate “from plow to plate” costs money. Such separation is called “identity preservation”. Who should pay for this?
Voluntary labeling works in the US for Kosher and Organic foods. Europe requires that all food that has any ingredient that is more than 1% GM be labeled as “GM containing”.
So, what’s the bottom line? 1.GM foods are as safe and there is promise for more nutritious food. 2.For some crops, environmental impacts are similar or less than conventional agriculture. 3.GM is an important tool for the plant breeder 4.GM technology can solve problems that can’t be solved in other ways at present. 5.The benefits will be spread between biotech companies, farmers and consumers.
GM or no GM is a false issue. Sustainability is the real issue. Through science and through ethics we have come to the realization that we are bound by the laws of Nature. We must obey those laws to make agriculture (and civilization) sustainable. Our agricultural practices must reflect our new awareness that many practices threaten sustainability. Food production must be equitable and just, and sustainable, for all the peoples of the Earth.