A GM-food primer. Not all GM-foods are created equal...

Last week's furor over genetically modified (GM) plants killing bees got me inspired to write a bit about genetic modifications. It's something I know a little about, as my day job is that of an academic post-doc in one of the larger medical schools in the U.S. I spend my days genetically modifying bacteria so that I can understand better how they work. Doesn't that mean that I'm biased? (I got called an industry stooge for defending GM-plants). Well, perhaps. But I earn so little that I have no money invested in biotech stocks (really, I have very little money invested in anything besides my house), so at least I have no financial horses in the race. And the work I'm talking about isn't really related to my own work. I'm just sufficiently educated in the field that I have a clue.

So, what did the Spiegel article mean when the author accused GM-plants of being responsible for the recent bee die-off? (a claim I debunk here and here). Do we need to worry that all GM-plants are killing bees? Well, no. They were talking about a particular, common modification called BT.

BT stands for Bacillus thuringiensis, which is just the latin name for a particular bacterium that kills insects. People started taking advantage of this bacterium over 70 years ago, by sprinkling dried bacteria onto plants to protect them from insects. (And even today, organic farmers consider this an acceptable pesticide that they are allowed to use). Indeed, the fact that it is a bacterium that only kills insects is of great use to us, as it is totally safe for humans.

Bacillus thuringiensis kills particular insects by virtue of a single protein that it makes. One gene specifies the creation of this protein. If you remove the gene from the bacterium, it no longer kills insects. What genetic engineers have done is to take the gene from bacteria, and place it into plants, particularly corn and cotton. (The insects that afflict corn and cotton growers are particularly susceptible to death by BT). So this one single gene is transferred from B. thuringiensis into corn or cotton, and allows the plant to kill insects that eat the corn or cotton.

Do we need to worry about BT harming people? No. In literally decades of study of B. thuringiensis, it has been shown that pure BT-toxin is no more harmful to people than table salt. You couldn't eat corn fast enough to accumulate enough toxin to give you so much as a bellyache (it is readily degradable in the stomach). And safety studies over the last 15 years have shown that BT-corn behaves no differently than B. thuringiensis sprayed on corn. Really, as much as you can say anything is safe, BT-corn is safe.

What about BT-corn harming bees? Well, folks have looked for this, too. But bees don't eat corn, and they don't pollinate corn. Indeed the dosage needed to kill bees is quite different than that of caterpillars and beetles, and the symptoms are rather different than what has been seen in the bee die-offs seen recently.

But, let's imagine for a moment that BT-corn is responsible for the bee die-off. Is this an indictment of genetically modified food? Not at all, it would be an indictment of BT-corn. There are all kinds of other modifications that people are working on that wouldn't have any kind of effect on insect populations. Take for example, coffee, genetically modified to not make caffeine. Or peanuts genetically-modified to remove the allergens. These are kinds of things that people are working on today, and one wouldn't expect there to be any kind of bad effects to people or plants by making these changes.

What I'm basically trying to say here is, when someone tells you they're talking about GM-food, it makes about as much sense to make general conclusions about it as it does when someone talks about "chemicals". Chemicals range in quality from vinegar to phenol to sulfuric acid. When speaking of the danger posed by these chemicals, there is quite a range of possibilities. So, too, with GM-foods. Each GM-food poses it's own risks and benefits, and current GM-foods, the risks seem rather small and the rewards rather large. I'll post in the future on some of the risks posed by newer GM-foods. But let's take these things on a case-by-case basis, shall we?

GM crops and bees, an addendum

At the moment, Colony Collapse Disorder (and this Spiegel article particularly) are causing a minor storm on the blogosphere. Many of the blogs are being fairly uncritical in their condemnation of GM-corn, with knee-jerk reactions predominating over reasonable analysis.

I found some interesting stuff from the Colony Collapse Disorder Working Group. This is a group of entomologists based out of Penn State that are trying to figure out why the bees in North America and Europe are dying. They're not quite as hysterical about the die-off as the conspiracy theorists at Spiegel:

During 2006, an alarming number of honey bee colonies began to die across the continental United States. Subsequent investigations suggest these outbreaks of unexplained colony collapse were experienced by beekeepers for at least the last two years. Reports of similar die offs are documented in beekeeping literature, with outbreaks possibly occurring as long ago as 1896. The current phenomenon, without a recognizable underlying cause, has been tentatively termed “Colony Collapse Disorder” (CCD), and threatens the pollination industry and production of commercial honey in the United States.

They have a number of likely suspects:

What potential causes of CCD is the Working Group investigating? The current research priorities under investigation by various members of the CCD working group, as well as other cooperators include, but is not limited to:
• Chemical residue/contamination in the wax, food stores and bees
• Known and unknown pathogens in the bees and brood
• Parasite load in the bees and brood
• Nutritional fitness of the adult bees
• Level of stress in adult bees as indicated by stress induced proteins
• Lack of genetic diversity and lineage of bees

but consider GM-corn (BT-corn) to be an unlikely suspect:

What are examples of topics that the CCD working group is not currently investigating?

GMO crops: Some GMO crops, specifically Bt Corn have been suggested as a potential cause of CCD. While this possibility has not been ruled out, CCD symptoms do not fit what would be expected in Bt affected organisms. For this reason GMO crops are not a “top” priority at the moment.

Radiation transmitted by cell towers: The distribution of both affected and non-affected CCD apiaries does not make this a likely cause. Also cell phone service is not available in some areas where affected commercial apiaries are located in the west. For this reason, it is currently not a top priority.

Now conspiracy theorists may point out that the working group hasn't completely ruled out BT-corn, but it is rather compelling that they have examined the deaths of these bees, and decided their deaths don't fit the symptoms expected by BT-poisoning. (Rather akin to finding a bullet hole in a corpse, and concluding that the person likely wasn't strangled).