Chapter 38

• Transgenic (genetically modified) organisms are those that have been engineered to express a gene from another species
• CRISPR-Cas9 gene-editing technology is rapidly changing plant biology
• Agrobacterium is a soil bacterium commonly used as a vector to genetically engineer plants
• An example of a naturally genetically modified plant is that a recent research concluded that an early ancestor of the sweet potato came into contact with Agrobacterium, and a horizontal gene transfer event occured
• Advantages of genetic engineering: not limited to genes of closely related species and much faster than traditional breeding
• Based on conservative population growth estimates, farmers will have to produce 40% more grain per hectare to feed the human population in 2030
• Genetically modified plants may increase the quality and quantity of food worldwide
• Some transgenic crops have been developed to produce the Bt toxin, which is toxic to insect pests but not vertebrates
• Genetic modification is used to improve the nutritional quality of plants
• "Golden Rice" is a transgenic variety being developed to address vitamin A deficiencies among the world's poor
• Transgenic cassava have increased levels of iron and beta-carotene and reduced cyanide-producing chemicals
• Some transgenic crops are resistant to the herbicide glyphosate (Round Up)
• Overuse has resulted in the evolution of glyphosate resistance in many weed species
• Glyphosate may negative effects on the health of humans and livestock
• Some people are concerned about the effects of GMOs on human health.
• Some biologists are concerned about risks of releasing GMOs into the environment
• Some opponents worry that genetic engineering may transfer allergens to a plant used for food
• There is no credible evidence demonstrating that GM food plants have allergenic effects on humans
• For example, maize that produces the Bt toxin has reduced infection by Fusarium, a fungus that produces a cancer-causing toxin
• Bt maize contains 90% less of the cancer-causing toxin than non-Bt corn
• Widespread adoption of Bt cotton in India has led to a 41% decrease in insecticide use and an 80% reduction in acute poisoning cases in farmers