Jul 27 2015

Artificially Selected Organisms

A new petition to Whitehouse.gov demands mandatory labeling for all “artificially selected organisms.” The petition says:

ASO plants or animals have had their genetic makeup altered to exhibit traits that are not naturally theirs. Artificial selection (or selective breeding) involves the selection of traits that are beneficial to humans, not what helps the organism survive in nature.

And concludes:

80% of Americans support mandatory labels on food containing DNA.

That last bit is true. A survey performed by¬†Oklahoma State University Department of Agricultural Economics found that 80.44% of Americans supported “mandatory labels on foods containing DNA.” That puts into perspective public support for mandatory labels on genetically modified organisms (GMOs).

The petition is obviously satire, and I think it represents the perfect use of satire – putting into sharp relief the illogic of a specific position or claim. This is a fight that happens almost every time a GMO supporter argues with a GMO critic. It goes something like this:

GMO Critic – GMOs are not natural. They are dangerous because they have been so drastically altered. At the very least we should show extreme caution.

GMO Supporter – Almost all the food you eat is genetically modified. Crops and domesticated animals look nothing like their “natural” predecessors. We have been modifying the food we eat for thousands of years.

GMO Critic – That’s different. Selective breeding and artificial selection are just using the traits that are already there. GM technology can take a gene from a fish and put it into a tomato, something which could never happen in nature.

I have seen some version of that exchange dozens of times, in the comment section of just about every article on GMOs. The reason the GMO supporter and critic cannot get on the same page is because they are often talking about two different things. A more detailed and precise discussion is necessary to get to the actual issues.

I do think the primary bit of poor logic is on the part of the GMO critic. They essentially begin their argument by saying that we should be cautious about GMOs because they are not natural. This is nothing but the naturalistic fallacy. There is no reason to believe that the makeup of plants that are the product of evolution without the intervention of humans are somehow safer or better for humans to consume than plants that have been altered by humans to be safer and better to eat.

Once this fallacy is pointed out they subtly change their position – it is not the natural vs artificial distinction they are making, but the specific methods used to create the artificial organisms. Their position becomes that radically altering plants through non GM methods is inherently safer than genetic modification.

Usually when they refer to genetic modification they are thinking of transgenic modification, taking a gene from an unrelated species that would not ordinarily be able to hybrid with the target plant. There is also cisgenic modification where genes from related species are used.

Either way, let’s explore that claim. A recent editorial by William Saletan in Slate (required reading for anyone interested in the GMO debate) nailed why the anti-GMO position is untenable:

They portray genetic engineering as chaotic and unpredictable, even when studies indicate that other crop improvement methods, including those favored by the same activists, are more disruptive to plant genomes.

Other crop improvement methods include crossing plants to make a hybrid, randomly exchanging hundreds of genes in the process. There is also mutation farming, in which chemicals or radiation are used to increase the mutation rate in the plants, creating more raw material for artificial selection.

GM technology, meanwhile, typically inserts a single gene (perhaps along with a marker gene, usually for resistance to a specific antibiotic). It is difficult to defend the position that randomly swapping hundreds of genes, or creating random genetic mutations, is somehow inherently safer than inserting a single target gene.

That is why the petition is so brilliant. It showcases the inherent hypocrisy of the anti-GMO position.

When confronted with these objections, GMO critics typically have two responses. The first is that artificial selection takes a much longer time, and therefore there is time to figure out if any unexpected traits have been created. GM technology is simply too fast. There is a sliver of truth here in that GM technology can create a specific desired trait much more quickly than previous methods. But the key phrase there is “desired trait.”

Other methods, like hybrids and mutation farming, quickly cause many changes to the plant genome – more quickly, in fact, than genetic modification. What takes time with these methods is that the changes are random, and so you have to keep trying until you get the desired trait or traits without undesired ones.

This brings us to the final objection of GMO critics, once the rest of their shaky logic is exposed. They argue that the one thing genetic modification can do that no other method can do is to take a gene from a distant species and put it into the target plant. In their minds this is what makes GMOs “frankenfoods.” They spread images of “fishmatoes” to make their point.

From a biological perspective the answer to this is – so what? This objection is based upon the emotion of disgust and a vague sense of purity, but not on science.

There is no such thing as a “fish gene.” There are genes that occur in fish, and about 60% of those genes also exist already in tomatoes and all other plants. Humans and bananas share 60% of their genes (admittedly, the number is somewhat arbitrary depending on how you make the comparison, but the point is still valid).

Once the gene is inserted into the tomato plant it does not see it as a “fish gene” – it sees it as a gene, just like any other gene. The genetic engineers may have to change the promoter region in order to make the genes compatible, but that’s no big deal. All living things on Earth (that we know of) share a common genetic code. A gene is a gene to all life on Earth. The only thing that matters is the code itself – for what sequence of amino acids does the gene code. The source is completely irrelevant.

The claim is also not factually correct. There are instances of horizontal gene transfer in nature. Recently, for example, it was discovered that sweet potatoes all have a gene from a soil bacterium. This is ultimately irrelevant – again only the gene matters, not the source – but it shows that the “natural” argument also misunderstands how nature works.

More sophisticated GMO critics may further argue that the process of inserting genes disrupts other parts of the genome. There is no evidence, however, that the changes that occur pose any inherent risk or are in any way significant. And again, the overall changes that occur are less than what happens with other breeding methods.

Also keep in mind that once a gene is successfully inserted, the plant is back bred to a desired cultivar several times until a stable line is created. In the end you get the desired cultivar plus the additional inserted gene – with a stable genome.

Conclusion

What is clear is that anti-GMO activists have decided, for whatever reason, that GMOs are evil.  They take this as an article of faith, and then backfill their objections to GMO. They use mutually conflicting arguments, inconsistent arguments, cherry-picked data and justifications that are ultimately based on emotion and not science.

In short, they use motivated reasoning just like any other science-denying group. Their arguments are the intellectual equivalent of antivaxxers or global warming deniers.

The “natural” argument is ultimately vacuous and inconsistent. This satirical petition shows one aspect of their inconsistency. It further shows (and Saletan argued very effectively) that the movement to demand mandatory labels for GMOs is misguided and ultimately hypocritical.

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