As you’re walking through the grocery store, you often see all sorts of logos on products: low sodium, high fiber, non-GMO. While some of these labels are clear, some of them are a little more confusing. What exactly is a GMO? How is it different from other foods? Are non-GMOs safer or healthier? Throughout the next couple weeks, I’ll answer all these questions and more as we demystify the mysteries behind GMOs. For today, let’s start with the basics: How does food change?
Humans have been modifying the genes and DNA (basic cellular instructions) of plants and animals for thousands of years. Even the earliest humans knew that if they bred only their most fruitful crops, they could greatly increase their agricultural yields. By breeding together the juiciest watermelons, early farmers developed the watermelon from a dry, thick-rinded cultivar to the sweet, juicy one we know today. This process is known as “artificial selection” and is still used for some purposes, but it has several limitations. Only pre-existing traits can be amplified through this method; a farmer can’t make blue peaches by breeding together their yellow peaches. To do this, the farmer would need to introduce a second species. This can be done through cross-breeding. In cross-breeding, new traits are introduced by breeding together members of different species. For example, the farmer would find a blue plum tree to breed with their yellow peach tree in order to produce blue peaches. While cross-breeding increases the number of beneficial traits available to farmers, it also introduces harmful traits. Blue peaches might look cool, but they could also taste terrible. Finally, only a limited number of traits can be added this way. Cross-breeding requires traits to come from similar species, so if the desired trait doesn’t exist in a similar species, it can’t be introduced. Since there is no such thing as a blue plum, our farmer would be unable to produce a blue peach through cross-breeding.
In order to introduce new traits, our farmer might turn to random mutagenesis. Random mutagenesis is the process of intentionally causing mutations (or changes to the DNA) to produce a desired trait. In this process, organisms are subject to high levels of radiation that damages parts of their DNA, causing hundreds of mutations. Since DNA has the instructions for an organism, the damaged DNA changes how they function. Usually, mutations have negative effects; however occasionally, they can introduce new, beneficial traits to the species. Eventually, one of the many organisms affected by random mutagenesis produces a desired trait amidst all the negative ones. This positive trait then has to be isolated from the negative ones by breeding the organism until all the undesired traits have been removed.
Together, artificial selection, cross-breeding, and random mutagenesis have determined the genetics of our food for thousands of years. In the past couple decades, however, the emergence of new technology has led to the creation of GMOs. Next time, I’ll go over what exactly GMOs are, how they’re made, and how this new technology compares to the ones we’ve been using for millenia.
Post By: A Guest Contributor
Photo credits: United States Department of Agriculture (USDA), https://www.ams.usda.gov/rules-regulations/be/symbols
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