by Gabriel Rangel
figures by Anna Maurer

Summary: To date, scientists have engineered bacteria that produce medication-grade drugs, crops with built-in pesticides, and beagles that glow in the dark. While these are all relatively recent advances in scientific technology, humans have been altering the genetics of organisms for over 30,000 years. How did the original practice of selective breeding evolve into the concept of genetically modified organisms, as we know it today? Innovators, motivated by some of the world’s most critical problems, have paved the way for GMOs — a path that leads to an unimaginable array of benefits, but also raises extremely important questions.

The concept of “genetically modified organisms,” or GMOs, has received a large amount of attention in recent years. Indeed, the relative number of Google searches for “GMO” has more than tripled since late 2012 [1]. However, humans have been genetically modifying organisms for over 30,000 years [2]! Clearly, our ancestors had no scientific laboratories capable of directly manipulating DNA that long ago, so how did they do it, and how have GMOs become such a popular topic?

Ancient Genetic Modification

While our ancestors had no concept of genetics, they were still able to influence the DNA of other organisms by a process called “selective breeding” or “artificial selection.” These terms, coined by Charles Darwin, describe the process of choosing the organisms with the most desired traits and mating them with the intention of combining and propagating these traits through their offspring. Repeated use of this practice over many generations can result in dramatic genetic changes to a species. While artificial selection is not what we typically consider GMO technology today, it is still the precursor to the modern processes and the earliest example of our species influencing genetics.

The dog is thought to be the first organism our ancestors artificially selected. Around 32,000 years ago, while our ancestors were still hunters and gatherers, wild wolves in East Asia joined groups of humans as scavengers. They were domesticated and then artificially selected to increase docility, leading to dogs that are closely related to what are currently known as Chinese native dogs [2]. Over millennia, various traits such as size, hair length, color and body shape were artificially selected for, altering the genetics of these domesticated descendants of wolves so much that we now have breeds such as Chihuahuas and corgis that barely resemble wolves at all! Since this time, artificial selection has been applied to many different species and has helped us develop all sorts of animals from prize-winning racehorses to muscular beef cattle.

Artificial selection has also been utilized with a variety of plants. The earliest evidence of artificial selection of plants dates back to 7800 BCE in archaeological sites found in southwest Asia, where scientists have found domestic varieties of wheat [3]. However, one of the most dramatic and prevalent alterations in plant genetics has occurred through artificial selection of corn. Corn, or maize, began as a wild grass called teosinte that had tiny ears with very few kernels [4]. Over the hundreds of years, teosinte was selectively bred to have larger and larger ears with more and more kernels, resulting in what we now know as corn.  A similar process has given us large heads of broccoli, bananas with nearly unnoticeable seeds, and apples that are sweet and juicy.

Although artificial selection is an ancient process that is still used today, most current conversations regarding GMOs refer to a much more modern process of altering the genetics of organisms.

The Birth of Modern Genetic Modification

An enormous breakthrough in GMO technology came in 1973, when Herbert Boyer and Stanley Cohen worked together to engineer the first successful genetically engineered (GE) organism [5]. The two scientists developed a method to very specifically cut out a gene from one organism and paste it into another. Using this method, they transferred a gene that encodes antibiotic resistance from one strain of bacteria into another, bestowing antibiotic resistance upon the recipient. One year later, Rudolf Jaenisch and Beatrice Mintz utilized a similar procedure in animals, introducing foreign DNA into mouse embryos [6].

Although this new technology opened up countless avenues of research possibilities, immediately after its development, the media, government officials, and scientists began to worry about the potential ramifications on human health and Earth’s ecosystems [7]. By the middle of 1974, a moratorium on GE projects was universally observed, allowing time for experts to come together and consider the next steps during what has come to be known as the Asilomar Conference of 1975 [8]. At the conference, scientists, lawyers, and government officials debated the safety of GE experiments for three days. The attendees eventually concluded that the GE projects should be allowed to continue with certain guidelines in place [9]. For instance, the conference defined safety and containment regulations to mitigate the risks of each experiment. Additionally, they charged the principal investigator of each lab with ensuring adequate safety for their researchers, as well as with educating the scientific community about important developments. Finally, the established guidelines were expected to be fluid, influenced by further knowledge as the scientific community advanced.

Due to the unprecedented transparency and cooperation at the Asilomar Conference, government bodies around the world supported the move to continue with GE research, thus launching a new era of modern genetic modification.

Use of Genetically Engineered Organisms

In 1980, the U.S. Supreme Court of the ruled that scientists from General Electric could patent bacteria that were genetically engineered to break down crude oil to help with oil spill mitigation [10]. This ruling legally permitted ownership rights over GMOs, giving large companies the incentive to rapidly develop GMO tools that could both be useful and profitable.

Two years later, in 1982, the United States Food and Drug Administration approved the first human medication produced by a genetically modified organism. Bacteria had been genetically engineered to synthesize human insulin, allowing them to produce enough of the hormone to purify, package, and prescribe it to diabetes patients as the drug Humulin [11].

While uses for genetic engineering range from oil spills to medication, perhaps the most controversial application is for food production. The first field experiments of food crops that had been genetically modified using recombinant DNA technology began in 1987. After five years of extensive health and environmental testing, Calgene’s Flavr Savr tomato became the first food crop to be approved for commercial production by the U.S. Department of Agriculture. These tomatoes were modified to include a DNA sequence that inhibited production of a natural tomato protein, increasing the firmness and extending the shelf life of the Flavr Savr variety.

In addition to making food more aesthetically pleasing, scientists have developed crops that are easier to for farmers to cultivate. In 1995 the first pesticide-producing crop was approved by the U.S. Environmental Protection Agency after rigorous testing [12]. A year later, Bt corn was approved, and now the majority of corn in the U.S. has the Bt toxin gene (see this article). Additionally, crops have also been genetically engineered to resist herbicides, making it easier for farmers to control unwanted plants in their fields. Perhaps the most famous herbicide resistant crops are the Roundup Ready or glyphosate-resistant plants (see this article). The first of these glyphosate-resistant crops was a variety of soybean, engineered by Monsanto in 1996. Now glyphosate-resistant technology has been applied to many other crops, including corn and sugar beets.

Scientists have also genetically engineered crops to increase nutrition value. For instance, Golden Rice was developed in 2000 with the goal to combat vitamin A deficiency, which is estimated to kill over 500,000 people every year (see this article)[13].

Although many species of animals have been genetically engineered, the vast majority of this technology is used for research purposes, and to date, there have been no GE animals approved by the FDA for use in food production [14].  However, in 2009, the U.S. FDA approved the first biological product produced by a GE animal, ATryn, a drug used to treat a rare blood clotting disorder [15].

Genetically Engineered Food Controversies

There have been many controversies regarding GE technology, with the majority relating to GE food. While some critics object to the use of this technology based on religious or philosophical bases, most critics object on the basis of environmental or health concerns. For instance, a 1999 publication showed Bt toxin had negative effects on butterfly populations in laboratory tests, leading to strong objections of Bt use, but follow-up studies in actual farming fields confirmed the safety of this technology [16]. In a different example, the economic stress of the poor yield of GE cotton crops in India over the late 1990s and early 2000s was associated by many organizations with a presumed increase in farmer suicides [17]. However, it was later concluded that suicide rates were actually unchanged after introduction of GE cotton, and that there were economic benefits of GE cotton for most Indian farmers [18].

During the same time frame, public awareness of the existence of GE foods increased, and calls for regulation of GE food grew louder, resulting in labeling requirements for GE food in many countries. Today, 64 countries have mandatory labeling laws for GE food [19]. However, the United States still does not have a mandatory, nationwide labeling law, although many advocacy groups are lobbying to enact one. These groups argue that labeling GE food is important for consumer choice and for monitoring unforeseen problems associated with the technology [20]. In contrast, groups opposing labels claim a law would unnecessarily eliminate consumer demand for current GE crops, causing steep increases in food price and resource utilization [20].

Although the debate about GE food is active, and there is no shortage of opponents to the technology, the scientific community has largely come together and concluded consumption of GE food is no more dangerous and eating traditionally selected crops  [21]. This conclusion has not stopped businesses from capitalizing on the current fear of GE food. In 2013, Chipotle became the first restaurant chain to label menu items as “GMO,” and in April of this year, the company announced the elimination of all ingredients made with GMOs, citing their “food with integrity journey” [22].  With cases such as this, it is safe to say the debate on GE food will continue for some time.

The Future of GMO Technology

There are countless potential uses of GE technology in development. These include plants with superior disease and drought resistance, animals with enhanced growth properties, and strategies for more efficient pharmaceutical production [23].  Likewise, GE technology itself is quickly advancing. Recently, researchers have developed a new technology called CRISPR, which takes advantage of bacterial systems to simplify genetic editing, allowing for easier development of GE organisms [24]. This technology could be used to expedite development of useful GE crops, facilitate disease elimination, or even alter entire ecosystems. Interestingly, recent advances in plant breeding techniques may increase the utility and rebound the popularity of the more traditional GMO method of selective breeding. Indeed, new drought resistant strains of various crops have been recently developed using traditional breeding methods [25].

The United Nations predicts that by 2050, humans will need to produce 70% more food than we currently do in order to adequately feed the global population (see this article) [26]. Indeed, innovative approaches will be required to solve this problem, and genetically engineering our food is a potentially useful tool. As scientists look forward at ways to create better crop survival, yield, and nutrition, it is important that we remember where all of this work began, and give credit to the pioneers who have made our advancements possible. Our ancestors that selectively bred wolves to eventually develop Corgis could not foresee that today we would be able to genetically engineer corn to withstand pests, herbicides, and drought. What is the future of GMO technology that we ourselves can’t foresee now?

Gabriel Rangel is a Ph.D. candidate in the Biological Sciences in Public Health Program at Harvard University.

This article is part of the August 2015 Special Edition, Genetically Modified Organisms and Our Food.


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  3. Balter, M. “ Farming Was So Nice, It Was Invented at Least Twice.” Science, July 2013.
  4. “The Evolution of Corn.” Genetics Learning Center, University of Utah, July 2015.
  5. Cohen, S. et. al. “Construction of Biologically Functional Bacterial Plasmids In Vitro.” PNAS, November 1973.
  6. Jaenisch, R. and Mintz, B. “Simian Virus 40 DNA Sequences in DNA of Healthy Adult Mice Derived from Preimplantation Blastocysts Injected with Viral DNA.” PNAS, April 1974.
    7.  Committee on Recombinant DNA Molecules. “Potential Biohazards of Recombinant DNA Molecules.” PNAS, July 1974.
  7. Berg, P. “Asilomar and Recombinant DNA.” Nobel Media AB, August 2004.
  8. Berg, P. et. al. “Summary Statement of the Asilomar Conference on Recombinant DNA Molecules.” PNAS, June 1975.
  9. “Biotechnology.” Encyclopedia Britannica, 2015.
  10. Altman, L. “A New Insulin Given Approval for Use in the U.S.” The New York Times, October 1982.
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  12. Ye et. al. “Engineering the Provitamin A (β-Carotene) Biosynthetic Pathway into (Carotenoid-Free) Rice Endosperm.” Science, January 2000.
  13. “Genetically Engineered Animals: Consumer Q&A.” U.S. Food and Drug Administration, June 2015.
  14. “FDA Approves Orphan Drug ATryn to Treat Rare Clotting Disorder.” U.S. Food and Drug Administration, February 2009.
  15. Sears, M. et. al. “Impact of Bt corn pollen on monarch butterfly populations: A risk assessment.” PNAS, August 2001.
  16. Heeter, C. “Seeds of Suicide: India’s Desperate Farmers.” Frontline World: PBS, July 2005.
  17. Gruère, G. et. al. “ Bt Cotton and Farmer Suicides in India.” International Food Policy Research Institute, October 2008.
  18. “Labeling around the World.” Just Label It Campaign, July 2015.
  19. “Labels for GMO Foods Are a Bad Idea.” Scientific American, August 2013.
  20. “A Decade of EU-Funded GMO Research.” European Union, 2010.
  21. Zimmer, C. “Chipotle Says Adios To GMOs, As Food Industry Strips Away Ingredients.” NPR News, April 2015.
  22. “Frequently Asked Questions on Genetically Modified Foods.” WHO, 2015.
  23. Ledford, H. “CRISPR, the Disruptor.” Nature, June 2015.
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19 thoughts on “From Corgis to Corn: A Brief Look at the Long History of GMO Technology

  1. Pingback: The Case for GMOs
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  3. Selective breeding is not GMO process.
    It is very misleading at best and looks more likely intentionally deceiving, as this paper is trying to describe monsanto’s GMO process as the continuous progression of selective breeding. Selective breeding does not involve inter-species DNA modification. It is very irresponsible of Harvard allowing this kind of article to be published knowing that this will be used to legitimize Monsanto’s GMO products. Shame.

    1. The article says: “most current conversations regarding GMOs refer to a much more modern process of altering the genetics of organisms.” The point is that humans have been influencing the DNA of our food supply for a long time. Furthermore, many of the most modern GMO technologies (many of which are not being developed by Monsanto, btw) don’t actually add any foreign DNA from other organisms or species, but rather delete or silence genes that the organism already has, which is very similar to what happens in selective breeding. You can read more about that in other articles in this special edition:,

  4. The simple question would be “what is the motivation of this article?” When GMO is currently associated mostly with monsanto’s GMO products/push (with foreign DNA insertion – which is core of what people are opposing to), why trying to group all GMO into the same umbrella? It is like to including America’s independent war and France’s resistant (La Résistance) in a history of terrorism. In a technical matter, some may argue the validity of assertion but highly inappropriate. especially coming from Harvard website.

    1. Not sure I am entirely understanding your point here, but the motivation of this article is to look at the many ways in which humans have altered the genetics of our food or other organisms to our advantage–through selective breeding or genetic engineering.

  5. What a tremendous disappointment this article is. It is not only misleading but it really sounds like a proGMO industry article, full of outright lies. I’m really not surprised that Harvard put their name on such an article.

    1. We at SITN try to be very careful about not presenting false information. If you have identified such information in this article, please provide a contradictory peer-reviewed source, and we will be happy to correct it. Thanks!

  6. It is very misleading at best and looks more likely intentionally deceiving, as this paper is trying to describe monsanto’s GMO process as the continuous progression of selective breeding. Selective breeding does not involve inter-species DNA modification. It is very irresponsible of Harvard allowing this kind of article to be published knowing that this will be used to legitimize Monsanto’s GMO products.

  7. Honestly the information published by gmo project is a lie and is just increasing food prices. No one truely knows anything and the fact that people think everything is being gmo-ed is stupid. we can help cure world hunger and blindness in Asia.

  8. When a scientific organization or research department purposefully conflates selective breeding through reproductive means and the genetic manipulation of biotechnology, the breaking, disrupting and forced replacement of DNA sequencing–an obvious and radical departure from the historic application/definition of the term ‘genetic modification, I am infuriated and I immediately discount the article and its author(s). Anyone with a basic knowledge of biology, chemistry and nutrition knows these processes are radically different and the campaign to mislead and conflate as though they are not should be discredited, individual scientists and entire labs, participating in this con should be publicly called out and held accountable for their abuses. We must insist as a scientific community that the term ‘genetic modification’ and current GMO research is *not interchangeable* and stop normalizing the conflation and promoting industry efforts to confuse the two. Manipulating proteins and breaking a sequence that is recognizable and bio-available is not the same as manipulating and isolating for expression in reproduction. You know this.

    1. I think the author is pretty clear that modern genetic engineering and selective breeding are not the same (if you read the whole article): “Although artificial selection is an ancient process that is still used today, most current conversations regarding GMOs refer to a much more modern process of altering the genetics of organisms.”

      Also, while I agree with you that selective breeding (which generally results in loss of genes or changes to genes that a plant or animal already has) is pretty different from the GE foods that are currently available (which add foreign genes that could never be gained from selective breeding), newer GE technology that uses CRISPR or RNAi to prevent expression of or otherwise alter genes that the plant/animal already has would pretty much achieve the same result as selective breeding, but faster.

      Given that we are in a global climate crisis, if we intend to keep feeding the billions of humans, we’re likely going to need our food to “evolve” faster than it will by “natural” means. GE technology as a solution to the world’s problems is too often dismissed as “unnatural” when it may be one of few feasible solutions to food crises of the future. While you accuse us (a grad student organization of scientists with no ties to big companies) of comparing GE technology to selective breeding in order to promote industry’s narratives, I can assure you this is not our intent at all (what would we gain from that?). Our intent is to fight against the public perception of “frakenfood” and “unnatural” evil GMOs because, based on our scientific education, we believe that that perception is hugely overblown. And we’re not alone–the gap between what scientists think about GMOs (that they’re safe) and what the public thinks is greater than the gap between scientists and the public for climate change! So yes, this article makes some comparisons between selective breeding and GE tech, but it also states that they are different.

      We also have other articles that support the regulation and testing of GM foods and explain some of the environmental dangers of currently available GM foods–such as the formation of superweeds. We are aware that there are some dangers of using GE technology in foods if it’s not carefully monitored, but we’re not ready to dismiss it outright!

      Since it sounds like from your comment that you may also be a scientist, I would be interested to know what, specifically about GM foods/GE tech has you concerned.

  9. The comments on this article, by majority, are proof that this is a terrible time to be intelligent. People’s opinion of a matter directly influences what facts they accept. They call this article misleading for integrating two human influenced concepts, but the title of the article is clear. “From Corgis to Corn:”. If you’d like to argue, please link your article with peer-reviewed scientific sources. If you can’t find one, write one with your independent study and open it for peer review. If you fail a peer review, it may be that all these bandwagon beliefs you’ve adopted are inaccurate.

    I can’t stand all these biased naysayers. argue by presenting facts to the contrary, not by saying “this looks like GMO/Monsato propaganda!” Without facts supporting that claim, YOU’RE THE ONES PUSHING PROPAGANDA.

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