From purple tomatoes to increasingly large ears of corn, genetic engineering is everywhere and has been creeping onto our plates over the last few decades. But how did civilization get to this point and what does it mean for your food?

A history of genetic engineering

Most of the food we eat today has been grown through traditional breeding methods that date back over 30,000 years. These conventional breeding processes, sometimes referred to as “selective breeding” or “artificial selection”, involve mixing genes (through sexual intercourse) from two different sources, such as plants or animals, to produce a desired trait in their offspring. We may not think of this approach as relating to modern genetic engineering, but the two principles rely on the same idea: you can influence an organism’s DNA through selection to produce desired traits. 

A good example of this can be seen in dog breeding. It is sometimes hard to believe that modern breeds like Pugs and Chihuahuas share the same genetic lineage as a German Shepard or Irish Wolfhound, but all these distinct dog breeds come from prehistoric wolves that were domesticated by humans. 

Although we are not sure exactly when this domestication first took place, why it happened, or where, we do know that dogs split from their common wolf ancestors around 27,000 to 40,000 years ago, during the Upper Paleolithic period, when we were still hunter-gatherers. It is generally believed that domestication occurred through a process of selective breeding, where specific wolves who exhibited useful traits were chosen to live with humans. This likely included selecting animals for their hunting skills and docility – because who wants to live with an animal that is aggressive or scared of you? 

Over the centuries, various additional traits were selected, such as size, hair length, color, body shape, and mating behavior, which changed the dogs’ genetics to such an extent that many dog species no longer resembled their wild ancestors. 

Similarly, artificial selection has been utilized with plant species. The earliest examples of the concept being practiced on plants date back to around 10,000 years ago in Southwest Asia where humans domesticated and bred einkorn wheat to improve its grain dispersal. 

One of the most impressive, and dramatic, transformation of a crop species through artificial selection is corn. What started out as a wild grass called teosinte, which produced small ears with few kernels, was gradually bred over many centuries to have increasingly larger ears and more abundant kernels. Through this process, we gained the type of corn we know today. This same method has also given us other crops such as broccoli with larger heads, sweeter and juicier apples, and bananas that contain smaller seeds.  

Selective breeding may work to produce desired changes in a species of organism, but it is far too slow to depend on in the modern world. This is where modern genetic engineering techniques come into play. These techniques can achieve results that would otherwise take generations to produce through natural selection. They also take place in a laboratory using specific processes and technologies to transfer genetic information from one species to another. 

What are genetically modified organisms – and how does it relate to food?

In the early 1970s, two scientists developed and demonstrated a technique that would change the future of genetics. In 1973, Herbert Boyer and Stanley Cohen were able to use an isolated enzyme to cut a string of DNA from one organism and to effectively paste it into another. In this instance, they took the gene associated with antibacterial resistance from one strain of bacteria and inserted it into a different species, thus giving it the same resistance. Boyer and Cohen had just created the first genetically modified organism (GMO). 

The revolution had huge impacts not only on our understanding of genetic engineering, but also practical considerations for pharmacology and medical treatments. Their work was soon followed in 1974 by that of Rudolf Jaenisch and Beatrice Mintz who introduced foreign DNA into mouse embryos. 

How did they achieve this? To create a GMO, you start by identifying the genetic information, or gene, that gives an organism – be it a plant, animal, or microorganism – a desired trait. That information can then be copied through the use of various techniques, but often through a process called recombination. As with Boyer and Cohen’s example, recombination involves cutting up DNA with an enzyme, called a restriction enzyme, and then combining (or splicing) that DNA with that of a different species, or to create genes with distinct functions. The cut DNA is attached into place with another enzyme called DNA ligase. Once the process is complete, the copies are usually referred to as recombinant DNA.

The genetically altered cells or microorganisms are then cultivated, and many new copies are created that exhibit the new gene. By specifically introducing genes for desired traits from a donor organism, the new organism can be free of other unwanted genes that may appear through traditional breeding techniques. For example, when plant breeders want to introduce a new trait to a plant species, they do so through cross-pollination, which can also introduce other genes into the species that lead to unwanted characteristics. Genetic engineering is therefore a far more precise method for achieving the same outcome.   

What are the controversies surrounding genetically modified food?

Genetically modified (GM) food has been on the market since the 1990s, especially in the US, and generally relates to plant products, such as genetically engineered tomatoes, corn, cotton, canola, soybeans, sugar beets, apples, potatoes, and more. The creation of these products is governed by strict regulations in most countries and they are required to meet specific health and food requirements before they are sold. The existing scientific evidence and research has shown that regulated GMOs are safe and do not pose a threat to consumer’s heath. 

Despite this, controversy still surrounds GMOs as food. Objections have been voiced on various religious and philosophical grounds, but they mostly focus on GMOs impact on health and the environment. In particular, the idea that GM food can cause cancer. However, there is no evidence that such foods cause cancer, nor is it clear how they are imagined to do so. In a rare consensus, the scientific community has largely come together and concluded that GM foods are no more dangerous than traditionally produced foods. 

Objections based on their environmental impacts are more challenging, but ultimately, they tend to amount to criticisms of modern agricultural practices rather than GM food themselves. Crops do not damage the environment just because they are GM. Some farming practices use too many herbicides that have a negative impact on the environment, but this is also the case with non-GM crops. The same is true with weeds that are resistant to herbicides, which occurs because farmers repeatedly grow the same herbicide-tolerant crop and use the same herbicides. 

In many cases, these issues, regardless of whether they relate to GM or non-GM crops, can be solved through responsible agricultural practices. This could involve setting aside agricultural land to foster biodiversity, as well as rotating crops that are resistant to different pesticides, or using different pesticides to prevent resistant weeds from emerging. 

The future of GM food

With the increased threats and challenges posed by climate change, it is likely we will soon see a larger dependence on GM products. In fact, the United Nations has predicted that we will need to produce 70 percent more food than we currently do to feed the global population by 2050. At the same time, genetic engineering technologies are constantly improving and will play a vital role in this effort. 

At the moment, scientists are developing new crops that have superior disease and drought resistance, animals with improved growth potential, as well as more efficient pharmaceuticals. 

And new technologies, such as CRISPR, are making it easier to genetically edit crops. CRISPR uses bacterial systems to simplify genetic editing by way of the Cas9 enzyme that cuts DNA apart. Bacteria use this enzyme to fight off viruses; now scientists can use this process to tweak genes in many animals or plants. CRISPR technologies are faster and more accurate than GM approaches and so will have a huge impact on the future of food production. As well as this, gene-edited crops contain no foreign DNA, so unlike GMO's they are becoming less strictly regulated and vilified. 

However, this does not mean that traditional methods of selective breeding will go extinct. There are already new drought-resistant crops being developed through these older established methods. It seems the answers to our problems will rest with techniques that combine the old with the new.

All “explainer” articles are confirmed by fact checkers to be correct at time of publishing. Text, images, and links may be edited, removed, or added to at a later date to keep information current.