The ideal comparator for a toxicology study on a GM crop is the non-GM isogenic variety (genetically the same but only lacking the genetic modification), also called the non-GM parent variety. This non-GM isogenic variety should be grown in the same conditions as the GM variety. That way, any differences found from the GM diet can be traced to the genetic modification, without the confusing factor of different environmental conditions.

Dr. Judy Carman responds to Nathanael Johnson of Grist

Dr Judy Carman noted in her pig feeding study[1] that she did not use the non-GM isogenic varieties as the comparators for the GM feed because they were not available to buy commercially – as well as because the GM corn was a stacked (multi-GM trait) variety for which there is no one non-GM isogenic parent.

But Nathanael Johnson, the food writer for Grist magazine, criticized Dr Carman’s study in his series of articles on GM for not using the non-GM isogenic parent crops. He claimed Dr Carman “could have partnered with any researcher at a university in the United States, which have permission to study patented seeds.

GMWatch challenged Johnson’s claim, saying it wasn’t plausible that these materials would have been handed over to Carman’s team so easily.

Johnson contacted his source, the plant scientist Dr Kevin Folta, for his views. About the issue of accessing GM seeds for research, Folta wrote:

“She [Carman] could have asked me, any of my colleagues that work in corn here at my university, or any of the thousands of other independent researchers in the USA. Who did she contact that turned her away? Probably nobody. Any seeds used could easily be obtained under an Academic Research License and results distributed freely.”

Johnson then asked about the non-GM isogenic varieties. Folta replied:

“Seeds are available through Academic Research Licenses, no questions asked from most companies. Plus, if she really wanted to do the experiment and felt there was a vast conspiracy afoot, she could have the transgenic plants made for well under $1000 each line. Services exist to do this at U Nebraska, U Missouri and UC Davis.”

Johnson then contacted Dr Judy Carman asking for her take on Folta’s claims and whether he was being “led astray”.

Here is a slightly shortened version of Carman’s response, which we are publishing in the interests of informing the public about the difficulties that independent researchers still face in getting hold of the basic materials to do GMO safety research – the GM seed and its non-GM isoline (parent variety), free from restrictive conditions.

Dr Carman wrote:

GM crops are under patent protection. This means that you cannot go to a seed merchant to buy GM seeds to test. If you do, you will be presented with a legal contract (a technology user agreement) to sign that states that you will not do any research on the seeds and you will not give them to anyone else to do research on, either. I know, because we tried this approach and I”ve seen the agreements.

We also approached GM companies directly, to ask them for samples of seeds to test. Responses from the companies varied, and I don”t have time to provide several paragraphs on the details, but none would consider our request until we did certain things first. We considered that no sensible independent scientist would accept the conditions, particularly as there was no guarantee that we would actually get seeds after we did everything they wanted.

The way that “US schools” get access to GM crops is by signing legal agreements with GM companies to be able to access the patented materials and patented methods that allow them to be online slots able to do GM crop work. They usually do this using commercial in confidence agreements that you or I cannot see, so we cannot see the conditions placed upon the researchers and the institutions involved, but there has been some protest from scientists about the conditions placed upon them that has been published in scientific journals. Also, clearly, GM companies will only reach these agreements with “US schools” that they approve of. They would not reach agreement with schools they do not approve of. The schools they approve of tend to be schools that work in partnership with the GM company to make GM crops where both can benefit financially. These legal agreements would certainly NOT allow the school to pass GM material on to me, particularly where the patent on the GM crop is not owned by them but by a GM crop company. Doing that would violate laws.

“You cannot make a GM crop, field test it and grow enough of it to feed that many pigs for that long a period for $1000. Whenever a GM crop company makes a GM crop, it takes many years and costs millions of dollars. Furthermore, we were interested in GM crops that are grown commercially in the US and currently in the animal feed and human food supply. The genes in these crops are patented and the patent is owned by someone. Taking a patented gene and putting it in a crop myself or asking someone to do it for me would violate quite a few laws.

As for isolines, as we state in the paper, there is no single isoline for the triple stack corn we used. The triple-stack corn was made by taking two or three GM crops and crossing them. Hence there is no single isogenic parent. Hence neither we nor anyone else can actually compare this GM crop to its isoline.

Furthermore, as we state in the paper, the GM industry regularly compares its GM crops to non-isogenic crops. Apparently, it is fine for them, but not for us. In addition, GM crop companies and regulators around the world have stated that GM crops are substantially equivalent and compositionally comparable to non-GM crops. Which means that they have in fact said that you do not need to compare the GM crop to its isoline. Folta appears to be disagreeing with all of them.

So yes, you are definitely being led astray.

Unfortunately, Johnson didn”t provide Dr. Carman”s full account in his article.  Instead, he wrote:

I’d noted that the researchers of a recent study comparing GM and conventional corn said  they couldn’t get genetic matches to GM feed because of intellectual property restrictions. But I assumed that they could have partnered with any researcher at a university in the United States that had permission to study patented seeds. GM Watch called this “touchingly naive,” which is actually quite a sweet sentiment (honestly), under the circumstances.

It’s true: I didn’t really know how hard it would be to find a collaborator with access to patented seeds. I emailed Judy Carman, director of the Institute of Health and Environmental Research in Australia and the lead researcher in the corn study. Carman responded that patents and restrictive contracts tie researchers’ hands and that GM food producers only cooperate with universities they approve of.

I also emailed Kevin Folta, a plant scientist at the University of Florida, who said just the reverse. He could have grown the corn because his university has free rein to experiment with patented seeds.

“She could have asked me, any of my colleagues that work in corn here at my university, or any of the thousands of other independent researchers in the USA,” Folta responded. “Who did she contact that turned her away? … Any seeds used could easily be obtained under an Academic Research License and results distributed freely. No problem.”

But, I pressed, wouldn’t it be harder to get the non-GM parent plants to use as a control? No, Folta replied, those seeds are also available under the agreements companies have made with universities: “no questions asked from most companies.”

Before 2009, some scientists really did have some trouble doing their work, due to patent restrictions. But the same scientists who protested the limitations now say the problem is largely fixed… I’m still standing by my assumption that, since 2009 at least, researchers have had much better access to GM seeds.



1. Carman, J. A., et al. (2013). A long-term toxicology study on pigs fed a combined genetically modified (GM) soy and GM maize diet. Journal of Organic Systems 8(1): 38–54.