In the early 1990s, an emerging disease destroyed Hawaii’s papaya production and
In the early 1990s, an emerging disease destroyed Hawaii’s papaya production and threatened to decimate the $11 million industry (Figure 1). Fortunately, Dennis Gonsalves, raised on a sugar plantation and then became a plant physiologist at Cornell University, would develop papaya plants genetically engineered to resist the deadly virus. By the end of the decade, the Hawaiian papaya industry and the livelihoods of many farmers were saved thanks to the free distribution of Dr. Gonsalves’s seeds.
Developing a new crop strain is an example of agricultural biotechnology: a range of tools that include both traditional breeding techniques and more modern lab-based methods. Traditional methods date back thousands of years, whereas biotechnology uses the tools of genetic engineering developed over the last few decades. Genetic engineering is the method scientists use to introduce new traits to an organism. This process results in genetically modified organisms or GMOs. For example, plants may be genetically engineered to produce characteristics to enhance food crops’ growth or nutritional profile. GMOs that are crop species are commonly called genetically engineered crops, or GE crops for short.
The History of Genetic Modification of Crops
Nearly all the fruits and vegetables in your local market would not naturally occur. In fact, they exist only because of human intervention that began thousands of years ago. Humans created the vast majority of crop species using traditional breeding practices on naturally occurring wild plants. These practices rely upon selective breeding (human assisted-breeding of individuals with desirable traits). Traditional breeding practices, although low-tech and straightforward to perform, have the practical outcome of modifying an organism’s genetic information, thus producing new traits.
An interesting example is maize (corn). Biologists have discovered that maize was developed from a wild plant called teosinte. Through traditional breeding practices, humans living thousands of years ago in what is now Southern Mexico began selecting for desirable traits until they could transform the plant into what is now known as maize. In doing so, they permanently (and unknowingly) altered its genetic instructions, allowing new traits to emerge. Considering this history, we might ask whether such a thing as “non-GMO” maize exists.
This history of genetic modification is common to nearly all crop species. For example, cabbage, broccoli, brussel sprouts, cauliflower, and kale were all developed from a single species of wild mustard plant (Figure 2). Wild nightshade was the source of tomatoes, eggplant, tobacco, and potatoes, developed by humans 7,000 – 10,000 years ago in South America.
Traditional Breeding v. Modern Genetic Engineering
To produce new traits in livestock, pets, crops, or other organisms, there almost always has to be an underlying change in that organism’s genetic instructions. What many people might not understand is th