Genes that keep out transgenes?

In the midst of literature review for a long, complicated post on gene flow between maize and teosinte (yes, this is how I spend my Saturday nights / Sunday mornings, thanks), I came across the following article in Science Daily from 12 October 2000: Gene Barrier In Corn May Boost Trade, Environment.

Working with teosinte, a wild cousin of maize, a University of Wisconsin-Madison scientist has found a molecular barrier that, bred into modern hybrid corn, is capable of completely locking out foreign genes, including those from genetically modified corn.

“This technology can potentially solve the problem of contamination of regular hybrid corn and organic hybrid corn by any genetically modified organism (GMO) during the growing season,” says Gerrish. “This technology could also allow a farmer to grow both types of maize crops and maintain a market segregated product.”

Using traditional breeding methods, the genetic barrier is being transferred to hybrid corn and testing quantities of seed should be available through seed companies in 2002, Gerrish says. Commercial quantities for planting by farmers are possible by the year 2003, he says.

How exciting! Does anyone know more about this? What is the status of the research? Has this trait been bred into any corn hybrids and used successfully to grow transgenic and non-transgenic maize side-by-side?

Dr. Jerry Kermicle. Image from his UW-Madison profile page.I looked for papers by Jerry Kermicle, Professor Emeritus of Genetics at UW-Madison, on Web of Science, PubMed, and Google Scholar. I found a few articles, including one similar to the SD story in EMBO reports (pdf), but no peer-reviewed articles exploring the potential of the incompatibility trait. I also looked for Steve Gerrish, the extension agent listed in the SD article, without luck. I was able to find the patent application: Cross-incompatibility traits from teosinte and their use in corn.

So, what is this? Another case of an over-exuberant press-release? Is this just another version of male-sterility? Am I just tired and missing something?

Note: If you read the SD article, you will see two mentions of insecticidal toxins and monarch butterflies. Just in case you didn’t already know, there is no danger to monarch butterflies from the Bt toxin in pollen. USDA ARS has put together a nice fact sheet about this.



  1. Interesting. Hadn’t heard about this, it does present some interesting possibilities. For instance, if it acts as a barrier for cross-pollination, would it make it harder to breed the corn that has it? That could be one reason why more information is hard to find about its current use, if at all. If it means you have to make tons more crosses, or add a complicated breeding scheme on top of your normal breeding program, breeders might not be very interested in it.
    Also, since it appears it is being licensed through WARF, and it is a naturally-occurring cluster of genes in teosinte, it sounds to me that the only way that they could prevent someone from breeding it into GE corn is if they use molecular markers. If there was a phenotypic way to select for it they probably couldn’t restrict its use completely.

    I also wonder if it is related in any way to the cross-incompatibility system in popcorn? Perhaps I’ll walk over to Genetics/Biotechnology someday this fall…

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