What is GMO?
This is the first part of a two (or more) part post inspired by my intense irritation from watching Jane Goodall last night on Bill Maher.
From countless posts on facebook and twitter to general media coverage, it has become increasingly apparent that the public doesn't really know what GMO is. Because I'm supposed to be doing a hundred other things right now, I thought it was a great time to write a blog post on GMOs.
Let's start with some definitions
Genetically Modified Organisms: Regarding the technical definition, GMOs are any life form that has had at least part of its genome (or genes) intentionally changed. This does not include changes that happen in nature (such as those from natural selection, evolution). These modifications are made Through techniques such as (1) conventional breeding; (2) mutagenesis, or (3) genetic engineering.
1. Conventional Breeding - In conventional breeding, plants are artificially "mated" or "cross-pollinated" to try to create plants with more desirable traits. Famous botanist Gregor Johann Mendel, for example, discovered rules of heredity when mating different types of pea plants. this process has been used for tens of thousands of years. This is how we have edible corn as compared to its ancestor, teosinte. While often alluded to as a type of GMO by the scientific community, the public does not view plants created through cross-breeding as GMOs.
2. Mutagenesis - In mutagenesis, genetic mutations are initiated by subjecting plant genomes to radiation treatments, or by exposing them to toxic chemicals. [Side note: This is the process by which many a superhero has gained his or her powers]. One real example of this is the ruby red grapefruit. Dr. Richard Hensz at Texas A&M worked to create the reddest grapefruit possible through ionizing radiation. Despite the general fear that words like "radiation" and "toxic chemicals" create, crops modified through mutagenesis are ALSO not what is viewed by the public as GMOs.
3. Genetic Engineering - The most precise way of altering the genome of an organism is through genetic engineering (see image below). A specific gene or sequence of genes is targeted and either turned on, turned off, or exchanged. There are a few methods for how this is done, usually using "biolistic transformation (aka the "gene gun") or through agrobacteria-mediated transformation. You can read about these processes in more detail here. It is crops that are created through genetic engineering that are referred to by the public as GMOs.
Source: ISAA Mentor's Kit, 2003.
Types of modifications made through genetic engineering
In addition to knowing what we are talking about when we say "GMO", it is also important to know that there are different types of modifications that are made.
1. Pesticide/Herbicide Resistance
The most infamous genetic modifications and the ones most covered in the media are herbicide resistant or "Roundup-ready" crops. These crops are modified to be resistant to the active ingredient in Roundup and other herbicide products, namely glyphosate. Some believe (and probably rightly so) that this will lead to an increased use of pesticides. However, it is important to make the distinction that it is not the modification itself that is bad but the behavior on the part of farmers that is potentially leading to the increased herbicide use.
While this is the most common and infamous modification, it is not the only one. And before our society decides to ban ALL genetically-engineered products, I think it is worthwhile to actually KNOW what the different types of genetic modifications are.
2. Nutritional Enrichment and Toxin Reduction
Some crops have been altered to provide better nutritional content than its natural counterpart. For instance, the International Rice Research Institute (NOT MONSANTO), a non-profit research organization, developed golden rice two decades ago. The purpose of golden rice was to act as a low cost method of improving the lives of people in Africa and Southeast Asia who were suffering from vitamin A deficiency which causes blindness and in some cases death. However, anti-GMO groups broke into the IRRI's research facilities and destroyed fields of the crop.
Also, some crops have been altered to prevent natural, harmful proteins from being made. For instance, did you know that when potatoes are fried, they release a carcinogren called acrylamide? Acrylamide is easily absorbed through the skin and distributed throughout the body. it has been found to cause neurotoxic effects in humans and animals. Thus, occupational safety organizations (such as OSHA) have set exposure limits. Switching to the genetically modified version of the potato would help alleviate this concern.
3. Environmental Stress/Climate Change Resistance
Some crops are also being developed to tolerate climate-based stressors such as drought, frost, and nitrogen starvation. For instance, drought tolerant corn has already been developed and many other crops are under testing. Use of these crops may be particularly important given the anticipated effects of climate change, particularly in lesser developed countries.
4. Pest Resistance and Virus Resistance
It is important to distinguish between pest resistant crops and pesticide/herbicide resistant crops. Tobacco, Corn, Rice, and many other crops have been engineered to express genes that lead to insects and other pests avoiding the crop, thus DECREASING the need to use pesticides.
Similarly, several crops have been saved from viruses that in some cases may have lead to the extinction of the plant and the destruction of the economy. For instance, in the late 1990s, there was an outbreak of the papaya ringspot virus in Hawaii, which threatened not only the crop but the entire industry and many jobs.
What genetically-engineered crops are on the market in the United States?
My final point for this post is that the public does not seem to know WHICH crops have been genetically-engineered, what crops are GMOs. In fact, articles have popped up claiming that gluten intolerance could have been instigated by the use of GM wheat (which does not exist on the market).
Here is a list of crops that are currently on the market as well as crops that are under evaluation or otherwise in the approval process
Currently on the market in the U.S.
I hope that this is helpful. I'll aim to post the next part of my blog on science consensus soon.