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Genetically Modified Food: How Did We Get Here?

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otanist examining plants in greenhouse
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Genetically Modified Organisms (GMOs)

In the early 1970s, ways were discovered to move genes for antibiotic resistance from one type of bacteria to another. The bacteria that received the gene, then became resistant to the antibiotic too.

This technology expanded to enable gene manipulation, not just in bacteria, but in plants and animals which are biologically much more complicated. As a result, genes that confer desirable characteristics, such as resistant to pesticides, immunity to viral diseases, or advantageous rates of growth can be inserted directly into a plant's or animal's DNA. This gene insertion produces a genetically modified organism (GMO) with a specific desired trait.

The First GM Food

The first genetically modified (GM) food sold was Flavr-Savr tomatoes, developed in the early 1990s by Calgene, Inc. The company was bought by Monsanto soon after the tomatoes were approved for sale. These tomatoes were engineered to suppress the polygalacturonase gene to delay how quickly they would soften after ripening.

Flavr Savr Tomatoes could be picked riper and kept longer than other varieties. However, to select the DNA that suppressed the polygalacturonase gene in the tomato, the researchers used a second gene that enables bacteria to be resistant to the antibiotic kanamycin. Flavr Savr Tomatoes, then, expressed this bacterial kanamycin resistance gene.

The slow softening of the tomatoes reduced the processing costs of making tomato products, like tomato paste, so they were used to make low-cost versions of canned tomato products that were sold in supermarkets in the Western US and United Kingdom. In 1998 after a UK scientist, Arpad Pusztai, expressed concern about GM foods on a British TV program, sales declined dramatically. Flavr Savr Tomato products went off the market in 1999.

The Engineered Papaya

A more recent example of an engineered fruit is the Rainbow Papaya. In the 1990s, the ringspot virus reduced Hawaiian papaya production by 40%. In response, Dr. Dennis Gonsalves, then at the University of Hawaii, engineered a papaya strain to make one of the ringspot virus genes (a virus coat protein) which made the papaya plant resistant to viral infection. The concept is similar to a vaccination.

Contrary to the perception of "big agriculture" pushing GM crops on the market, the Rainbow Papaya seeds were initially distributed free of charge and now are sold at cost by the non-profit Hawaii Papaya Industry Association. The Rainbow Papaya is the only GM fruit currently sold (except for tomatoes if you consider them a fruit).

Resistance to Ringspot Virus Was Only the First Step

While the gene-altered Rainbow Papaya saved Hawaiian papaya agriculture, the fruit's commercial success has been limited since a large part of the market for papayas is international. For example, Hawaiian papaya sales to Japan were $15 million in 1996, but only $1 million in 2010. Getting the Rainbow Papaya approved for sale outside the US has been a huge hurdle to its commercial success and true recovery of the Hawaiian papaya industry.

After more than ten years of lobbying, Japan finally approved sales of the Rainbow Papaya at the end of 2011, enabling Hawaii an opportunity to recapture its lost papaya market. Since the Rainbow Papaya will be labeled as GM food, however, it still remains to be seen how well the fresh tasty gene-altered fruit will overcome popular concern about GM food.

Grains and Seeds: The Real GMO Success

Although the availability of genetically modified whole foods is somewhat sparse, processed foods that include GM products have become a major commodities over the past dozen years.  The majority of approved genetically engineered food are major industrial crops such as corn, soy, and cotton (cottonseed oil is used in processed foods). In 2011, 160 million hectacres of GM crops were grown, 90% of which was in the US, Brazil, Argentina, India, and Canada. That's more than 10% of global crop land. Approximately 82% of cotton, 75% of soybeans, 32% of corn, and 26% of canola are genetically engineered.

While much of the GM crops go to animal feed and fuel, GMOs have now become common in groceries the Western hemisphere and India. Estimates are that about 70% of processed food sold in the US and 60% of processed food sold in Canada contains genetically modified plants, most from GM soybeans and corn.  In contrast, only about 5% of processed on European store shelves contain GMOs.  

What about GM Animals?

Genetically modified transgenic animals are commonly made and used in research. For example, mouse models with extensive genetic engineering are a standard tool for drug discovery and development. However, so far, no GM animals have been introduced into the food market.

The dearth of GM animal food may soon change, though, if AquAdvantage Salmon is approved. AquAdvantage Salmon is Atlantic salmon with an additional unregulated Chinook salmon growth hormone gene inserted in its DNA. This gene from the faster growing Chinook salmon allows the AguAdvantage Salmon to grow larger more quickly than its natural cousins.

In Sept 2010, a review from the Veterinary Medicine Committee of the FDA that, "a large number of test results established similarities and equivalence between AquAdvantage Salmon and Atlantic salmon" with regard to food safety. However, while final approval for the salmon was expected within a few months after this review, it is still pending almost two years later.

No Easy Answers to GMOs

Are GMOs a dangerous and unnatural aberration of our food sources or a natural extension of modern technology to improve our food supply? Of course, it depends on who you ask. GM plants, at least, have rapidly become a significant and expanding part of the global food market.

Genetic manipulation through crossbreeding has been done for thousands of years to produce the agricultural revolution that resulted in domesticated corn and wheat, grotesque chickens, and hundreds of varieties of apples. These techniques have produced a global population of 7 billion. Today, genetic engineering may be the most effective way to further improve food production to meet the challenges of a growing global population. Will direct manipulation of DNA by genetic engineering herald next step in crop improvement and food development to meet the future challenges of feeding the world, or is it a risky endeavor that could lead to severe global health consequences?

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