London (22 August 2005) – Towards the end of 2001, startling information was published on the presence of transgenic maize genes in southern Mexico, a country that is home to Teosinte, the primitive forerunner of modern food maize and in which many local varieties (“Land races”) are cultivated. Where had the invading genes come from? What might they do to the genetic resources of this most significant of all Mexican agricultural resources?

The report about the offending genes, published in Nature (ref. 1), came from two scientists at the University of California in Berkeley. However, so powerfully were their data and conclusions challenged that in due course Nature actually reversed its assessment and withdrew the paper (ref. 2).

The anti-GM “environmentalists” were, of course, delighted, not only with the original report which appeared to confirm their direst predictions, but also with its subsequent withdrawal, a clear case (in their view) of intimidation and pressure from “industry” (ref. 3).

The media were quick to pick up both aspects of the story, with the Chairman of CropGen doing his best to inject some balance into story (ref. 4).

It has now rumbled on for nearly five years, a benchmark both for the opponents of transgenic technology in agriculture about how bad it can be and for the supporters about the way in which information is manipulated and used for political ends (other examples can be found on this website in the Highlights Archive (Death rattle of a scare story? [13.6.05] and Super hyperbole strikes again [26.7.05]).

But no longer. Definitive studies (ref. 5) have looked at 870 plants from 125 fields in 18 localities in the relevant area, and screened 153,746 seeds. to show categorically that genetically modified corn has not spread to native maize crops in southern Mexico. As well as upsetting the organised opposition (most of whom have yet to comment on their websites), it has also caused some embarrassment in the anti-GM press (ref. 6).

An Australian observer commented (ref. 7):

The response of some in the anti-GM community to this debunking of one of their favourite myths has been interesting. For example, Jonathon Matthews of GM Watch has attacked the ethics of Barbara Schaal, who edited the paper on behalf of PNAS, and obliquely suggested slight of hand in its publication (, see also arcid=5586). This criticism has included the strange disqualification that Schaal lives in St Louis, on the basis that it is Monsanto’s hometown.

The critics of GM crops frequently take the opportunity of lambasting promoters of GM crops for talking up the technology. After these recent events, would we be criticised for calling some of the anti-GM campaigners hypocrites?


1. David Quist, Ignacio H. Chapela (29 November 2001). Transgenic DNA introgressed into traditional maize landraces in Oaxaca, Mexico. Nature, 414, 541-543

2. Mexican maize madness (2002). ABC Online (

3. Maize Under Threat - GE Maize Contamination in Mexico (18 August 2003). Greenpeace (

4. Mexican study raises GM concern (28 November 2001). BBC News (

5. S. Ortiz-García, E. Ezcurra, B. Schoel, F. Acevedo, J. Soberón and A. A. Snow. Absence of detectable transgenes in local landraces of maize in Oaxaca, Mexico (2003-2004). Proceedings of the National Academy of Sciences of the United States, August 10, 2005, 10.1073/pnas.0503356102 (

6. John Vidal and Paul Brown (17 August 2005). Moral maize. The Guardian (,,1550052,00.html)

7. Christopher Preston (17 August 2005). Of Superweeds and adventitious presence. Studies in hyperbole: Of superweeds and adventitious presence. AgBioView (


  The saga of Mexican maize; another red herring bites the dust!