Jan 20 2017

Questions on GMOs

gmo-cartoons-good-fat-100Genetically Modified Organisms (GMOs) remain the one issue on which there is the greatest disparity of opinions between scientists and the general public. Even among self-identified skeptics, people who make a genuine effort to align their opinions with the scientific evidence, there remains great distrust of GMOs and the companies who produce them (such as Monsanto).

This disparity is partly due to the decades-long campaign by Greenpeace and the organic lobby to demonize GMOs. It is much easier to fearmonger than to reassure. I think we have started to crawl back toward reality on this issue, but we have a long way to go. We started with the low-hanging fruit, correcting the outright lies.

It is much more difficult to dispel the vague sense that there is something menacing about GMOs. We have a deep emotional connection to food that we perhaps don’t even recognize. It is easy to trigger our emotion of disgust, and we have apparently evolved to err on the side of avoiding anything that may be tainted. The image of unnatural “frankenfood” still clings to our culture and is hard to dispel.

I recently received the following question from an SGU listener, which I think represents such lingering unease:

My question is, given our current scientific research capabilities, are there any definitive studies out there than can reasonably predict the long term effects of GMOs in terms of our personal health and in terms of the potential environmental impact (ie. genetic biodiversity)? What are the techniques that we can use, given the potential long-term slow nature of a true impact on both of these aspects (wellbeing and environment)?

Do GMOs also introduce new risks to the world, in that modifications might start to be made in the name of profit/geopolitical purposes rather than social welfare? Perhaps a hopeless uncreative sci-fi inspired rogue GMO, that inadvertantly wipes out food supplies of another nation (an adaptation of the non-breedable mosquitoes concept to reduce the spread of malaria)?

I think that reasonable questions such as this go a long way to explaining the disconnect between scientists and the public. Even a reasonably scientifically literate skeptic could simply not understand the science of GMOs sufficiently to feel confident that they are safe.

First we need to distinguish the process from the end result. Produce being GMO only describes the process by which the cultivar was made. It says nothing inherently about the end result. Genetic modification, which is a bit vague as a category, usually refers to techniques that directly alter the genetics of a plant, rather than using breeding techniques. There are still some techniques that I think are in the gray zone, such as mutation farming, where chemicals or radiation are used to increase the rate of mutations and produce more variety to select and cultivate.

Direct genetic alteration can include silencing or altering a gene already present in the plant or inserting a new gene, which can come either from a closely related species or from a species from a different kingdom of life. It is this latter category that gets the most attention from critics, because it seems the most “unnatural.”

This brings up an important point. Biologists understand that all known life on earth share the same genetic code. A gene is a gene. Humans already share about 60% of our genes with plants. The “fishmato” perfectly represents this misunderstanding. One GMO program intended to insert a gene from a cold-tolerant fish into a tomato plant resulting in cold-tolerant tomatoes. This could extend the growing season for tomatoes, and increase productivity. This product was developed but never approved or marketed. The “fishmato”, usually depicted as a scary tomato with scales and fins, became a common anti-GMO meme.

Here’s the thing, however – tomatoes already share 60% or so of their genes with fish. Also, people eat fish, which I understand have lots of fish genes. The source of the gene is irrelevant. The tomato plant doesn’t know where the gene came from. All that matters is the protein that the gene codes for and what it does.  Meanwhile, in a Canadian survey, 22% of respondents thought that tomatoes modified with a fish gene would taste fishy.

As an aside, to be pedantically accurate, different kingdoms of life do use different promoters in their genetics, so when genes are taken from distant species sometimes the scientists do need to insert a promoter that will work in the recipient. This has no affect on the final product, though.

That same Canadian survey also found that:

” a significant percentage of the population believes that genetic modification also involves radiation and/or the injection of antibiotics, steroids and hormones into food and food products.”

Again – a vague sense that something unnatural is going on. People also think that GMOs are unnaturally large, and that they are mutants, like the X-Men, but plants. They might therefore be superpredators, or do things that no “normal” plant can do, which could wipe out our ecosystem. This is a fantasy.

All living things are mutants. There is no natural state for any gene. They are mutating all the time. Some genes are highly “conserved” which means their function is so critical and stable that they do not tolerate mutations, which are selected against when they occur. We share the same histones with peas, for example. But for most genes and proteins, which are mildly conserved, most genes are no more mutated than any other gene.

When biologists speak of mutations they are usually making a relative statement, about the amount of difference between genes. A mutation is a change, but the end result is not inherently biologically different than the source. It does not grant super powers, or make produce preternaturally large, or make them “unnatural.”

In other words, there is no such thing as a “mutant” really, only relative differences among species, breeds, and cultivars.

So are there any inherent or unknown risks to GMOs because they are “mutants?” No. The very question misunderstands biology and genetics.

This is often why scientists will point out that everything has evolved over time, and humans have artificially evolved almost all the food we eat with various methods. All of our foods are mutated from what occurred in nature prior to human intervention. GMOs are no more “mutants” than cultivars developed through breeding or hybridization.

The only real question is this – do any of the processes used in developing GMOs involve any specific or unique risks? The answer to that is no. This has been studied for decades now. Yes, GM techniques mess with the genome. That is kinda the point. But the full process involves back-breeding plants with an inserted gene to the parent cultivar until a stable new cultivar is developed. This is done until you have a new plant that is only different in that it contains the new desired gene.

We still study new GMOs carefully to make sure that any new proteins expressed are safe, and this is reasonable. We study them to make sure they are essentially equivalent to their parent cultivar, that no unexpected changes occurred.

The environment is particularly safe from GMOs. We are not creating invasive weeds. Scientists are creating crops. Crops by their very nature are not robust. They depend upon humans to provide optimal growing conditions for them, and to protect them from pests. We also made them more edible by reducing a lot of their natural defenses. Plants ordinary make a host of pesticides to protect themselves, but these can be bitter or harmful so we bred them out. In the wild, without humans to care for them, crops would mostly be frail. So don’t worry about them taking over.

Fear of GMOs is one area that might be particularly susceptible to education, because the more someone understands about the biology of plants and GMOs the less worried and more accepting they are of GMO technology.



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