If we’re going to label GMOs, let’s do it sensibly

In my last “Let’s talk biotechpost, I discussed how challenging it is to define whether a genetically improved plant is technically a “GMO”. Determining if a given food item contains genetically modified ingredients is even more difficult.

There has been a lot of recent discussion about GMO labeling. On one side, you’ll hear that consumers have the right to know whether or not food has been genetically modified. On the other hand, many argue that labeling GMOs is unnecessary and would stigmatize a perfectly safe crop improvement technology. Missing from much of this dialogue is an explanation of what would actually be labeled.

There are only a few GMO crops currently on the market in the United States: alfalfa, canola, corn, cotton, papayas, soybeans, squash, and sugarbeets. The majority of GMO crops grown do not show up in the produce aisle directly, but are used to feed animals (alfalfa, corn, soybeans), or for oils (cotton, canola, corn, soybeans) and sugars (sugarbeets, corn) in processed foods.

So where exactly might you find a GMO label if it existed?

1.GMOs or foods containing GMOS

This is obvious. Actual whole GMO produce such as pest-resistant sweet corn, or disease-resistant squash would be labeled. Processed foods obviously containing these ingredients such as salsa with GM corn or trail mix with dried GM papayas would also be labeled.

2.Meat/Dairy from animals fed GMOs

This is a bit trickier, and still up in the air. As Ben and Jerry’s points out on their website, eating a GMO does not make YOU a GMO. For this reason, they have advertised that their ice-cream is “GMO free” for years, even though it is made from the milk of cows fed genetically modified feed. This logic seems fair enough. After all, the gene that makes alfalfa a GMO cannot be found in a pint of Cherry Garcia.

3.Processed foods made with oil/sugar extracted from GMOs

As with meat/dairy, this is a toughy. Just as the genes unique to GMOs don’t make it through a cow’s gut, they also don’t show up in high-fructose corn syrup or soybean oil. These processed ingredients are 100% identical to organic alternatives.

4.Foods produced by (or with ingredients produced by) GM microorganisms

The production pipeline of some foods and food additives relies on genetically modified fungi or bacteria. Cheese is pretty much universally made using enzymes produced by genetically modified microorganisms. Genetically modified microorganisms can also produce vitamins, which can then be used to fortify cereals. This might explain why several vitamins went missing when Grape Nuts and Cheerios went GMO-free. The GM microorganisms themselves are not present in the final product, so the only difference is a decrease in vitamin A, B12, D and Riboflavin in the GMO-free version.

So which of these foods SHOULD sport the GMO label? It’s only physically possible to differentiate those in the first category, raw GMOs or foods containing whole GMOs, from their non-GMO counterparts. Those foods in categories 2-4 are completely indistinguishable from alternatives, so it doesn’t make a whole lot of sense to label them. Nonetheless, you could argue that if you wish to avoid GMOs for religious, economic, social, or environmental reasons, you might want to know if GMOs were used in any step of the production pipeline. In that case, all foods dependent on GM technology should be labeled as such, with no exceptions. Anything in between does not make any logical sense. Unless, of course, you’re Vermont and exempting milk and cheese happens to support your own economic interests…

All of the state-specific labeling initiatives thus far (failed in California, Colorado, and Washington, passed in Vermont) have proposed a patchwork mess with illogical exceptions. Any GMO labeling law upheld in the United States should be national and consistent with no exceptions. That’s my opinion. I’d be happy to hear yours in the comments section.


3 Surprising Facts About Plants: Immunity, Indeterminacy, and Immortality

As an undergraduate, I sat through human biology lectures, shouldered up with ambitious pre-meds at the University of Colorado. When they marched off to anatomy, I wandered into the councilor’s office, wondering what biology careers don’t require memorizing musculature.

I met with professor emeritus and plant biotechnology enthusiast Andrew Staehelin who insisted, “you should get a PhD in Plant Biology at UC Davis”. Thinking to myself “UC where?” I applied for a graduate program in a subject I’d never studied at a University I’d never heard of.

When I got to the University of California in Davis I learned two important things:

  1. “What’s your favorite plant?” is everybody’s favorite ice-breaker question
  2. “I dunno, the kind you eat” is not an appropriate answer

So when a seed company recruiter started my internship interview with “What’s your favorite…” I was relieved that she finished with “…thing about plants?” Now that is a question I can answer. After 4 years studying plant biology, I still don’t have a favorite plant, and my plant taxonomy skills are lacking, but I have learned a whole lot about how plants work from the brilliant faculty and students at UC Davis.

So as an-ex human molecular biologist who’s come over to the plant side, here are my three favorite things about plants:

  1. Immunity: Plants have immune systems too! Plant immune systems are actually somewhat similar to human and animal immune systems. They can even be vaccinated against viruses. For example scientists inserted a bit of DNA from the papaya ring-spot virus into the papaya genome. The resulting disease-resistant plants saved the Hawaiian papaya industry. Studying disease response in plants also contributes to our understanding of human disease pathology. In fact, microorganisms were first found to be a cause of diseases in plants! (Think Irish potato famine)
  2. Indeterminacy: All plant cells are indeterminate or “totipotent”-as in-“totally capable”. This means that every single plant cell acts as a stem cell, which, under the right conditions, can develop into a whole new plant. Check out this picture of a rose flower sprouting a whole new plant from the UC Davis Plant Transformation Facility. Screen Shot 2016-03-23 at 7.15.28 PMTotipotency is what makes “clonal propagation” possible. For example, all bananas are actually clones of one parent banana, the Cavendish. Instead of reproduction by seeds, every new banana plant is grown from the cutting of another. Many other food crops such as apples and strawberries are also clonally propagated.
  3. Immortality: Unlike animal cells, plant cells can essentially live forever. Although whole plants don’t typically live forever due to environmental factors, plant cells are not limited in the number of times they can divide. That’s why trees can grow for thousands of years, and seeds can germinate after tens of thousands of years.

In conclusion, plants are pretty amazing and very underrated. Plants tend to blend into the background of our existence, like buildings or landscapes. This phenomenon is called “plant blindness.” But plants are quite dynamic, and we rely on them for food, oxygen, medicine, fuel, fibers, and more. Further, plant research has significantly contributed to our understanding of human disease. Nonetheless, basic plant science is seriously underfunded and understudied. I hope to counter plant blindness by sharing facts and new discoveries in my “That’s Plantastic” segment. I’m happy to answer (or more likely find an expert to answer) any questions you have about plants in the comments section.

What is a GMO? This seemingly simple question is difficult to answer, and it’s about to get a whole lot tougher.

It’s no mystery that GMO stands for genetically modified organism, but what exactly does that mean? You might have heard claims like: “we’ve been genetically modifying organisms for centuries”

That’s arguably true. Modern corn is about as similar to its ancestor “teosinte” as corgis are to wolves. Breeding has allowed us to select for useful traits such as large golden grains or small docile canines.  Modern techniques help to speed up the slow, laborious breeding process. “Marker-assisted breeding” involves taking a tiny chip out of a seed coat, checking to see whether a target gene is present, and growing up only the winners. “Mutagenesis” involves using chemicals or radiation to randomly introduce mutations into a population of seeds, and selecting plants with improved traits. Surprisingly, crops produced this way are not regulated as “GMOs” and can even be certified organic.

So what crops are regulated as GMOs? All of the “GMO” crops currently on the market are “transgenic”. As the name implies, this means that a new/foreign gene has been inserted into these plants. This gene can come from bacteria as in herbicide-tolerant or pest-resistant corn, soybeans, cotton, alfalfa, canola, and sugarbeets. It can also come from a virus as in disease-resistant papayas and squash. Transgenic plants can even contain a gene from another plant of the same species. This is the case for the non-browning potatoes and apples coming to market soon.

Seems simple enough right? GMO’s have been directly engineered to contain novel genes. That definition has worked for a while, but now there’s a new trick in a breeder’s box of tools called CRISPR-CAS9. CRISPR-CAS9 is a bacterial defense system that  has all the features of Microsoft Word’s find/replace, cut, copy, and paste tools. It allows scientists to target extremely precise regions of the genome and make very specific changes. For example, if a single mutation is known to cause resistance to disease, scientists can now directly introduce that mutation into an existing gene. This change would be completely impossible to differentiate from a naturally occurring mutation. Nonetheless, many are calling to have plants altered in this way regulated as “GMO,” as they are technically genetically engineered.

So what should really qualify as “genetic modification”? Conventional or marker-assisted breeding, which involves shuffling and scrambling whole genomes? Mutagenesis, which causes unkown mutations at random sites throughout the genome?  Trans-genic technology, which involves adding a single gene that, depending on the gene, might have been possible to introduce by breeding on a much longer timescale?  Gene editing by CRISPR-CAS9 which causes one or a few precise changes to genes?

And these are only a handful of the many techniques used to improve crops. I haven’t even touched on grafting, protoplast fusion, polyploidy, or conventional breeding of non-compatible species with chemical assistance! You can see the issue is pretty complicated. Perhaps the real questions should revolve around risks not processes. Why continue to heavily regulate any crop produced by transgenic technology when every major scientific organization in the world has agreed the technique is no more inherently risky than conventional breeding? And why regulate crops produced by gene editing which causes one or a few precise changes, but not those produced by mutagenesis which introduces many unknown mutations?

I’m happy to hear your civil and respectful thoughts on which crop improvement technologies should fall under the GMO umbrella in the comments section.

For more resources, there is a great infographic by Dr. Layla Katiraee of Integrated DNA Technologies comparing different crop improvement techniques, and a very thorough analysis of the GMO definition problem by Grist science journalist Nate Johnson titled “It’s practically impossible to define ‘GMOs’



Hands-on Activity: Central Dogma of Biology

As part of the Sacramento Powerhouse Science Center’s Science Communication Fellows Program, I worked with educators to develop a hands on teaching module to describe my graduate research at the University of California in Davis. I focused on the foundational subject of gene expression, sometimes called the “central dogma of biology”. In the central dogma, genes, which are functional units of DNA that encode traits, are copied into molecules of RNA. RNA is structurally similar to DNA and serves as a molecular message. The RNA is then used as instructions to construct the proteins that are responsible for recognizable traits in all organisms.


I found this hands-on activity to be effective in teaching basic concepts of genetics to students 10 and above as well as an enjoyable exercise for adults. The lesson had the dual function of explaining how genes encode traits and driving home the point that all of life is composed of the same basic building blocks, “the genetic code”.

Beads on pipe-cleaners were used to represent nucleotides (DNA building blocks) in a gene which was attached to a felt oval representing the nucleus (where the DNA is housed and copied) of a cell. I set the stage by describing a scenario in which some cells from my pet dog contaminated one of my samples of plant cells, and I needed to identify which gene belonged to the plant and which belonged to my dog, Fiona. There were two nuclei, each representing either the model plant Arabidopsis or Fiona the dog. The nuclei were fixed at one end of the table, while the “genetic code” needed to decode the gene was fixed at the other end of the table.

I then introduced a challenge: “Can you figure out: Which string of beeds represents Fiona the dog? Which string of beads represents the lab plants? The genes that make a plant a plant or a dog a dog are stored in a tiny cell compartment known as the nucleus, but the information needed to decode those genes to produce a trait (such as small or white) exists outside of the nucleus. Can you use the beads to make a copy of the message in the nucleus and then crack the genetic code to see if the message describes Fiona or the lab plants?”


There were three simple steps to unravelling the mystery. “Step 1: Pick a nucleus” (at which point I asked the students to guess if the nucleus they think represented the plant or the dog).

Step 2: Using a pipe cleaner, make an exact copy of the beaded message” (students followed the color code on their own piece of pipe cleaner, which they got to keep as a bracelet).

Step 3: Use the ‘genetic code’ on the other side of the table to decode the message. Each set of 3 beads represents the letter of a word used to describe the plants or the dog” (the encoded word was either ‘green’ or ‘furry’ depending on the nucleus). Conclusion: “Plants and dogs are very different, but the building blocks that make up their genes are exactly the same. Did you figure out which nucleus is which?”


After they had finished the exercise, I explained that what they’d just done is called gene expression, and it happens in cells all the time. “Genes are units of DNA. DNA is made up of four building blocks represented by the letters A, C, G, and T” -just like the four differently colored beads. DNA is locked up in the nucleus, but the machinery needed to translate its message into traits (proteins) is outside of the nucleus, so- “DNA is copied into a similar structure called RNA in a process called ‘TRANSCRIPTION’. This RNA message”-represented by their bracelets- “is also made up of four building blocks represented by the letters A, C, G, and U. The RNA message” -gets transported out of the nucleus, where it- “is decoded three letters at a time in a process called ‘TRANSLATION’. This process provides instructions for how to assemble the proteins that make up the physical traits of plants and animals.”

As an aside, I then went on to explain how we study gene expression in plants by making “changes to DNA then measur(ing) gene expression using a special gene that turns plants blue or fluorescent” and closed with a shameless plug for why plant science is so important and yet so under-appreciated.

I hope the reader finds this module useful for describing the central dogma in your own classroom/workshop settings.

Creative Commons License
Hands-on Activity: Central Dogma of Biology by Jenna E Gallegos is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
Based on a work at https://escapingthebench.wordpress.com/2016/03/20/hands-on-activity-central-dogma-of-biology/.