You Say Potato, I Say Protato

There’s been a buzz this past week about a genetically modified salmon that the FDA is considering approving for human consumption.  Meanwhile, as we await the FDA’s decision, an article has just been published in the primary literature (PNAS)Proceedings of the National Academy of Sciences about a new type of GMOgenetically modified organism – this time, a potato.

This special potato was designed with a different intention than the GM salmon; for that matter, it has a different purpose than really any of the GMOs that might currently show up in your pantry or refrigerator here in the U.S.  Most of the genetically modified foods to date have been altered to enable more efficient production.  For example, Monsanto’s Roundup Ready soybeans are designed to be resistant to the herbicide Roundup; this enables farmers to use the weed-killer more effectively, killing off unwanted weeds but doing less damage to the soy.  Along the same lines, the GM salmon has been engineered to grow bigger and faster than normal salmon, allowing more of this fish to make it to the market.

Unlike the soybeans and the salmon, the new potato in question has been designed with quality in mind, rather than quantity. The bioengineered potato is meant to be better for you than a regular potato: it has more protein.  This high-protein potato, aka a “protato” (I did not make this up), could arguably supply better nutrition to consumers, especially those in developing countries that rely on potatoes as a primary staple.

So what goes into genetically engineering a protato?

How it Works. Researchers introduced a new gene into a normal potato’s DNA.  This gene is new to the potato, but not new to nature – it’s a gene that codes for the production of a certain proteinspecifically, AmA1 in amaranth plants (a protein that doesn’t normally exist in potatoes).  To sneak this gene in, the researchers used well-known genetic engineering tricks.  They put small pieces of DNA, containing the code for the protein, into bacteria cells where the genes easily became incorporated into the bacteria’s own DNA (bacteria have a penchant for taking up new chunks of DNA). This particular type of bacteriaAgrobacterium tumefaciens is one that attacks plants, and has an unusual mode of action.  Upon infection, this bacteria is able to force a piece of its DNA in the plants’ own DNA.  Thus, the researchers were able to use the bacteria as little Trojan horses to sneak the protein gene into the potato’s DNA.

Once they had successfully introduced the new gene, the scientists grew generation after generation of these GM potatoes.  They always chose the strongest and most protein-rich plants to carry on to the next generation.  After several generations, they feel confident in claiming that the gene is stable in the potato plants.

Key Concerns and Results. The paper discusses several important concerns about the potato that the researchers had to address, including protein content and quality, possible toxicity and allergenicity, and palatability.

They found that the potatoes had up to 60% more protein in them than normal potatoes. Furthermore, they contained a more diverse range of amino acids (building blocks of proteins).  The researchers next performed a series of animal tests and other analyses to check for toxicity and allergenicity.  These tests involved such things as feeding potatoes to rats, rubbing potatoes on rabbits’ skin (they didn’t get any rashes), and performing various experiments analyzing the chemical makeup of the potato and checking for known allergens.  They concluded that the potato was safe for human consumption.

One the last things they did was to fry up some protato chips. The researchers don’t comment on whether or not they tasted this lab experiment (though it’s hard to imagine they didn’t), but they analyzed the cooking quality of the potatoes through various high-tech means.  The conclusion?  These protatoes cook up just as nicely, if not better, than any old potato.

Discussion. Although I hope to not delve into the controversiality of GMOs too much, one particular scientific concern was not addressed within the scope of this paper. A common fear in the context of GMOs is that an arguably unnatural organism could have an unforeseen negative effect on the environment.  For example, environmental groups are concerned that the GM salmon, if it escapes into the wild, could outcompete the normal fish for food and disrupt the current balance of life.*

However, the possible environmental impact of the protato isn’t really explored in this paper.  Certainly this is one concern that will have to be addressed if the protato is to ever be featured on our dining tables.

*This fear can be partly allayed by knowing that 99% of the GM salmon are sterile – they can’t have babies. They also lack certain survival skills: when they see a shadow above the water, they think it’s feeding time and come to the surface.  A normal salmon sinks down when it detects a shadow, fearing that it’s a predator like a hawk.
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