Good Gene – Bad Gene: When GMOs Succeed and When They Don’t

As we saw in a previous post, genetic engineering has recently been successful in greatly accelerating the development of vaccines for COVID-19. Genetically engineered crops, which date back about 30 years, have also scored a number of successes, but there have also been some notable failures.

To some environmentalists, tinkering with a food plant’s genes conjures up pictures of “Frankenfoods,” evocative of the monster created by the fictional mad scientist Frankenstein. But such irrational fears over food safety and the planet’s ecology, aggravated in the past by the cavalier attitude of agribusiness companies, are a rejection of science.

The clash between environmental activists and the agricultural behemoths is epitomized by the success story of Golden Rice. Golden Rice is genetically modified to contain beta-carotene, a naturally occurring pigment that produces vitamin A in the human body and imbues the grain with a characteristic yellow color. The GMO (genetically modified organism) has been developed as the answer to vitamin A deficiency in many parts of Asia and Africa, where millions of poor children die or go blind each year from weakened immune systems caused by a lack of the vitamin.

But as soon as Swiss plant geneticist Ingo Potrykus and German biologist Peter Beyer triumphed in splicing the two necessary genes – one from daffodils, one from a bacterium – into rice, widespread hostility erupted, despite a wave of publicity about their accomplishment and a feature article in Time magazine in 2000.  

Golden Rice was dismissed as “fool’s gold” by Greenpeace, who claimed that a person would have to eat about 9 kilograms (20 pounds) of cooked Golden Rice per day to meet the daily requirement for vitamin A. However, this far-fetched claim was repudiated by the subsequent development, reported in 2005, of an improved Golden Rice with 20 times as much vitamin A-generating beta-carotene. Other detractors saw the genetic engineering feat simply as a Trojan horse, as a vehicle for launching other more profitable GMO crops in the developing world.

Many further barriers lay in the two scientists’ path. These included bomb threats against Potrykus, necessitating construction of a bombproof greenhouse; obtaining free licenses to 70 patents belonging to 32 different companies and universities that the discovery had potentially infringed on; and crossbreeding required to insert the magic daffodil and bacterium genes into suitable varieties of rice, research conducted at the nonprofit IRRI (International Rice Research Institute) in the Philippines.

Nonetheless, in 2018, four countries – Australia, New Zealand, Canada and the U.S. – finally approved Golden Rice. The U.S. FDA (Food and Drug Administration) has granted the biofortified food its prestigious “GRAS (generally recognized as safe)” status. IRRI applied for approvals in rich countries initially, in order to avoid trade disruptions arising from small quantities of GMO rice finding their way into non-GMO rice sold to other countries.

An example of a GMO food that never made it to market is a soybean containing a gene from Brazil nuts. Seed supplier Pioneer Hi-Bred International wanted to bolster the nutritional content of its soy-based animal feeds, which must normally be supplemented with an amino acid called methionine to promote adequate growth of the feeding animals. Because the Brazil-nut protein 2S albumin is very rich in methionine, Pioneer planned to splice the 2S albumin gene into the soybean genome.  

But mindful that Brazil nuts can cause strong allergic reactions in humans – though the specific allergen was previously unknown – and that soybeans intended for animals can’t easily be separated from those destined for human consumption, the company commissioned testing of its transgenic soybeans for allergenicity.  

Sure enough, 2S albumin was found to be not only a human allergen but also present in the genetically altered soybeans, revealing that genetic engineering can indeed transfer food allergens from one plant to another. The positive test results, reported in 1996, would have required Pioneer to label its new product for sale in the U.S., under the FDA protocol for allergy testing in transgenic plants. Instead, the company dropped its marketing plans for the soybeans.

Another example of a potential GMO food that didn’t come to fruition is potatoes genetically engineered to produce their own pesticide. In this case, the idea was to make potatoes pest resistant via a gene borrowed from that harbinger of spring, the snowdrop flower. Despite its delicate appearance, the flower harbors a type of sugar-bearing protein known as a lectin that is toxic to certain kinds of preying insect.

A major furor erupted in the late 1990s over research on laboratory rats fed with lectin-modified transgenic potatoes, and claims by the researcher that the GMO potatoes stunted the rats’ growth and degraded their immune systems. But controversy over a scientific review of the research that found the experiments were invalid put a stop to any further development of potatoes engineered with the snowdrop gene. Today, the only GMO potato approved for human consumption is a nonbruising variety.

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