GMOs (genetically modified organisms) are often perceived something like “Grossly Monstrous & Odious.” What are they anyway?
Strict definitions of GMOs usually refer to transgenic organisms: those that have had a gene from other species inserted into them. The techno name for changing DNA is mutagenesis, but transgenic mutagenesis not the kind of change to DNA that routinely happens in nature, which rarely involves entire genes [but see this super cool example of how entire fungal genes made it into wheat without modern tools]. Think GloFish, or Round-Up Ready. These are precise insertions of a single gene that is then expressed by another organism, making glowing tissue or resistance to a glyphosate pesticide.
There are nearly infinite possibilities.
Targeted gene deletion is another precise method. In agriculture, it could be used to delete a gene that makes a protein that a virus uses to attack an organism, thus making it resistant. I’m not sure that this has been used commercially yet.
A newer technique, using Crisper-cas9, can edit existing genes without having to insert an entire gene from another organism. These GMOs are not transgenic in the same way, because they do not have a gene from another organism, but a modified copy of their own gene.
All of the organisms we use for agriculture have been genetically modified by humans. We have been doing this since long before we knew that genes existed. Normally, the genetic modification techniques we used before transgenic organisms were created are not referred to as GMOs. But that doesn’t mean that they have not been extensively genetically modified by humans.
Hybridization is one way in which half of an organism’s genes come from a different species. This is done by forcing species to mate in a relatively controlled environment. This might make them heartier as well. Think mules from horses and donkeys. Most of our grain crops come from ancient or not so ancient hybrids. Most humans are ok with this in terms of its use in agriculture because it seems to happen “naturally,” even though these hybrid species may not naturally succeed in the wild. GMO-free labels allow for this kind of genetic modification.
Selective breeding can delete genes from a population by choosing those individuals that don’t display the selected trait. This takes advantage of spontaneous mutation that has resulted in different versions of the same gene. Through selective breeding, desirable genes are “fixed” in a population, which means undesirable ones are effectively deleted. GMO-free labels also allow for this kind of genetic modification.
Selective breeding usually involves many genes instead of a single gene. In some cases, this might result in organisms resistant to certain pests or that always give us the type of fruit we want. Through selective breeding, traits can be fixed accidentally, because as we select for traits we want, we are unaware that we are also selecting for the deletion or inclusion of other traits that we are not measuring. This might make a crop more susceptible to pests.
All of the above are just a few of the examples of the ways humans have been genetically modifying organisms for at least thousands of years. When someone reads “GMO-free” on a package at a store, though, it usually means that it was developed using the messy tools of hybridization and selective breeding and not precise ones, like those used in transgenic organisms.
Many people are afraid of the precise tools (i.e. GMOs), and refuse to support their development. They may refuse to buy these products, or actively try to ban techniques that introduce these organisms into our food supply. There were effective movements to try to force the labeling of GMO crops, and the US has Public Law 114-214 that regulates their labeling. As I write this over 60 countries require labeling of some sort.
Every GMO organism is different, and therefore, calling an organisms a GMO doesn’t mean that it shares any trait with another GMO. It just means that it was modified precisely. The messy way to modify organisms is referred to as conventional breeding. Some consider this way of breeding to be natural, though scientifically it is referred to as artificial selection because it is not a process that occurs in nature.
It is impossible to demonstrate that GMO crops are a health risk in general because each one is different. It is possible to demonstrate that a particular genetic modification of a particular crop is a health risk. In the U.S. the Food and Drug Administration, the US Department of Agriculture, and the Environmental Protection Agency work together to regulate these products.
All GMOs on the market have been demonstrated to be safe for their approved use. Conventional breeding does not have to prove safety in the same way that GMOs do, because they are generally assumed to be safe.
There is a lot of misinformation out there about GMO crops. Those who oppose them often seem not to understand them. I hope this helps people to understand when the person talking about GMO crops does not actually know what they are talking about.