Friday, June 21, 2013

The NewLeaf Tragedy

Now, anyone who knows me knows that I'm opinionated: I'm not often ambivalent on “issues” because I think about them and decide which side I'm on, and genetically modified organisms — GMOs — are no different. So, here's the thing: I'm generally, though not unreservedly, in favor of GM technology subject to appropriate safeguards. I think most public opposition is a lazy bandwagon, fueled by a Luddite echo-chamber of mindless and ignorant fear-mongering activism that is impervious to evidence and reason. I think GMO-free products and “organic” produce are no more than a brilliant marketing tool to separate the gullible from their money.

One absolutely magnificent scientific achievement, an unqualified good for humanity, was killed by Luddism and ignorance: Monsanto's NewLeaf potato.

To understand what happened, the background begins with a family of pesticides collectively called “Bt” (for the harmless soil bacterium, Bacillus thuringiensis, from which they are derived). Bt is generally regarded as harmless to the extent that it is approved for use on certified “organic” crops with zero wait-time between spraying and harvesting; it is produced by breeding vats of one of a handful of B. thuringiensis strains and extracting the spores or the active pesticidal proteins: the Cry family of δ-endotoxins, and spraying on crops in suspension. Different Cry proteins are toxic to different ranges of insect species, so each different Bt strain yields a fairly narrow-spectrum insecticide depending on what exact Cry protein combination the particular Bt strain expresses. The usual targets are coleoptera (beetles) and lepidoptera (butterflies and moths), the most pestiferous insect classes, but avoiding hymenoptera (bees, wasps, and ants), which are generally benign or even useful (some Bt strains express proteins that are toxic to certain sawflies, but not other hymenoptera). Cry proteins have been confirmed to be entirely non-toxic to vertebrates, but might be immunogenic to humans in high doses. Technical details aside, Bt is, or was, widely used on potatoes to control the Colorado potato beetle, an endemic pest that is devastating to potato crops.

The other piece of background information that you need is that the Russet Burbank potato is the most widely grown potato cultivar in the US, preferred for french fries by fast food chains, and is widely grown on a very large scale for this purpose.

Now, Monsanto succeeded in splicing the Cry3a gene from Bt into the Russet Burbank potato — this was the NewLeaf potato — so that it would express a protein known to be toxic to the Colarado potato beetle at a few ppm (part per million) in the leaves, sufficient to kill them, but totally harmless to us (the Cry3a protein concentration in the tuber is less than 180 parts per billion; at this concentration, it wouldn't matter if it was strychnine). Clever, eh? No, not just clever: a bloody marvel of modern science is what it was. We should've had a ticker-tape parade for these guys.

NewLeaf was a massive success. Half of Idaho grew it. It was in every french fry you ate for several years. Then the Luddite activists stepped in. It was “dangerous”, they said. It was “unnatural”, they said. It was “frankenfood”, they said. It was harmless and brilliant. It contained the same pesticide that's sprayed on their beloved “organic” produce by the ton, the only difference was how it got there.

Unfortunately, the PR campaign to demonize NewLeaf was a massive success too. Misinformed consumers revolted; fast food chains stopped buying NewLeaf potatoes; farmers stopped growing them; and, after a few iterations (there were later “versions” of NewLeaf with different genes), Monsanto stopped producing them altogether because there was no demand any more.


Now, there are basically two purposes for which genes are spliced into crops like potato, soy bean, and corn:
  • Pesticide expression (such as the Cry3a protein in NewLeaf)
  • Herbicide resistance (such as glyphosate resistant “Roundup Ready” soy)
I have no problem with either of these, and I see no way that either of them can plausibly cause any harm. I've explained the situation with NewLeaf in detail, and glyphosate is actually pretty innocuous stuff that basically breaks down readily in the soil.

My concern is that transgenic crops have been so massively successful that, in some cases, it can be difficult for farmers to get seeds that aren't genetically modified, and their choice of what to plant should be preserved. It seems like there may be a risk of a monoculture arising, which history (the Irish Potato Famine of the mid 19th century, for example) suggests is a really bad idea.

Provided that the availability of a wide range of cultivars is preserved, I see no reason to fear GM.

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