In this half-hour special, QUEST Northern California explores genetically engineered crops in the wake of Proposition 37, the 2012 ballot initiative that would have required foods containing genetically engineered ingredients to be labeled in California. Prop 37 lost, but some 6 million Californians voted in favor of labeling, signaling that many aren't completely comfortable with genetically engineered food.
Are the benefits of genetically engineered foods worth the risks?
Next Meal: Engineering Food explores how genetically engineered crops are made, their pros and cons, and what the future holds for research and regulations such as labeling.
Ever wondered what genetically engineered crops and other foods are in the pipeline?
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Conventional plant breeding vs. genetic engineering – 5 differences:
1. When did we start using each technique?
Plant breeding is some 10,000 years old – as old as agriculture itself.
“The ancestors of tomatoes were the size of my thumb and they tasted very bad,” said Eduardo Blumwald, plant biologist at the University of California at Davis. “And breeding gave us what we have right now.”
In the mid-1990s, tomatoes genetically engineered in California were made into a tomato paste that sold well in England. But the tomatoes were short-lived. Photo: Alan McHughen.
The first genetically engineered food to be commercialized, the Flavr Savr tomato, was sold by Calgene, a Davis company, starting in 1994. The tomato was engineered to stay firm on the vine for longer, but it was short-lived.
Monsanto, the Missouri-based seed company, started selling genetically engineered soybeans and cotton in 1996. The soybeans tolerate the herbicide Roundup, so that farmers can spray it on weeds without hurting their crop in the process. The cotton keeps away pests like the bollworm.
2. How do these two techniques work?
“Classical plant breeding involves taking the female eggs from one plant and bringing them together with the male parts of another plant,” said Peggy Lemaux, plant biologist at the University of California at Berkeley. “And then all that genetic information gets mixed up. Half of the information in the progeny – or children – of that cross comes from the mother and half comes from the father. And it just all gets mixed up.”
Depending on the plant, breeders use different strategies to cross them. Corn breeders, for example, gather pollen from female plants and shake it onto male plants. Plants such as cucumbers usually contain both female and male flowers on each plant. Breeders remove the male part from one flower and attach it to a female flower.
Plant biologist Peggy Lemaux, at the University of California-Berkeley, uses a "gene gun" to genetically engineer crops like corn.
In contrast with breeding, genetic engineering involves only one or a few genes.
“With genetic engineering, it’s just moving very small parts of the genetic information. You might take it out of one plant and move it into another plant,” said Lemaux.
In genetic engineering, genes can be transported into a plant by a type of soil bacterium. Or they can be injected into a plant using a tool called a gene gun.
3. What can you do with each one?
Classical plant breeding allows scientists to do things like breed disease resistance or a higher-protein content into crops like wheat, said Jorge Dubcovsky, leader of the wheat breeding program at the University of California at Davis.
But when they’re breeding, scientists have to cross plants that are closely related to each other.
“Classical breeding is done between closely related plants, so you might take a wild variety of rice, for example, and you could cross that with modern cultivated rice,” said Peggy Lemaux. “However, maybe there are traits that you want, that you can’t find in a wild variety of rice. Maybe you want to introduce some vitamin or mineral, and you can’t find a wild rice species that would give you that particular trait. So what you have to do is you have to go and find some other organism that does make, let’s say, vitamin A, and you can pull that information out from that plant and put it in.”
In that scenario, genetic engineering would be required. Engineering would also be required to tweak a gene in such a way that it produces more or less of a desired trait.
4. Is conventional plant breeding low-tech, while genetic engineering is high-tech?
Genetic engineering can be more expensive than conventional plant breeding, and is usually faster. But this doesn’t mean that breeding is as low-tech as you might think. In the past 15 years or so, plant breeders have been able to speed up the crossing process by using genetic markers.
“The markers allow me to see the genes that I have bred into a plant,” said Jorge Dubcovsky.
Many genes that scientists set out to breed into plants are difficult to see and expensive to find within the plant. A genetic marker is a piece of DNA that is easy to see and inexpensive to find within a plant. So scientists identify the markers that are on either side of the gene they’re trying to breed into a plant. This way, when they have crossed their plants to contain that gene, they can easily and inexpensively find out which plants contain their gene of interest by looking for the markers, rather than for the gene. Markers are like tiny flags on either side of the gene that make it visible to researchers.
5. Do scientists do either one or the other?
Usually, some researchers specialize in plant breeding and others in genetic engineering. But both types of scientists work closely to improve crops, said Eduardo Blumwald, who is genetically engineering rice to be drought-tolerant.
“We are placing new genes in those varieties which plant breeders have bred,” said Blumwald.
