Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Transgenic DNA introgressed into traditional maize landraces in Oaxaca, Mexico


Concerns have been raised about the potential effects of transgenic introductions on the genetic diversity of crop landraces and wild relatives in areas of crop origin and diversification, as this diversity is considered essential for global food security. Direct effects on non-target species1,2, and the possibility of unintentionally transferring traits of ecological relevance onto landraces and wild relatives have also been sources of concern3,4. The degree of genetic connectivity between industrial crops and their progenitors in landraces and wild relatives is a principal determinant of the evolutionary history of crops and agroecosystems throughout the world5,6. Recent introductions of transgenic DNA constructs into agricultural fields provide unique markers to measure such connectivity. For these reasons, the detection of transgenic DNA in crop landraces is of critical importance. Here we report the presence of introgressed transgenic DNA constructs in native maize landraces grown in remote mountains in Oaxaca, Mexico, part of the Mesoamerican centre of origin and diversification of this crop7,8,9.

This is a preview of subscription content, access via your institution

Access options

Rent or buy this article

Prices vary by article type



Prices may be subject to local taxes which are calculated during checkout

Figure 1: PCR amplification of DNA from the maize-specific alpha zein protein gene (top panel) and the CMV p-35S promoter (centre and bottom panels).
Figure 2: Inverse PCR sequences of flanking regions adjacent to the CMV p-35S in landraces (A2, A3 and B3) and in Diconsa seed (K1).

Similar content being viewed by others


  1. For communications arising from this paper, see Nature advance online publication, 4 April 2002; DOI 10.1038/nature738; DOI 10.1038/nature739 and; DOI 10.1038/nature740.


  1. Losey, J. E., Raynor, L. S. & Carter, M. E. Transgenic pollen harms monarch larvae. Nature 399, 214 (1999).

    Article  ADS  CAS  Google Scholar 

  2. Saxena, D., Flores, S. & Stotzky, G. Insecticidal toxin in root exudates from Bt corn. Nature 402, 480 (1999).

    Article  ADS  CAS  Google Scholar 

  3. Ellstrand, N. C. When transgenes wander, should we worry? Plant Physiol. 125, 1543–1545 (2001).

    Article  CAS  Google Scholar 

  4. Doebley, J. Molecular evidence for gene flow among Zea species—genes transformed into maize through genetic engineering could be transferred to its wild relatives, the Teosintes. Bioscience 40, 443–448 (1990).

    Article  Google Scholar 

  5. Ellstrand, N. C., Prentice, H. C. & Hancock, J. F. Gene flow and introgression from domesticated plants into their wild relatives. Annu. Rev. Ecol. Syst. 30, 539–563 (1999).

    Article  Google Scholar 

  6. White, S. & Doebley, J. Of genes and genomes and the origin of maize. Trends Genet. 14, 327–332 (1998).

    Article  CAS  Google Scholar 

  7. Wang, R.-L., Stec, A., Hey, J., Lukens, L. & Doebley, J. The limits of selection during maize domestication. Nature 398, 236–239 (1999).

    Article  ADS  CAS  Google Scholar 

  8. Piperno, D. R. & Flannery, K. V. The earliest archaeological maize (Zea mays L.) from highland Mexico: new accelerator mass spectrometry dates and their implications. Proc. Natl Acad. Sci. USA 98, 2101–2103 (2001).

    Article  ADS  CAS  Google Scholar 

  9. Iltis, H. From teosinte to maize: the catastrophic sexual transmutation. Science 222, 886–894 (1983).

    Article  ADS  CAS  Google Scholar 

  10. Matsuoka, T. et al. A method of detecting recombinant DNAs from four lines of genetically modified maize. Shokuhin Eiseigaku Zasshi 41, 137–143 (2000).

    Article  CAS  Google Scholar 

  11. Gachet, E., Martin, G. G., Vigeau, F. & Meyer, G. Detection of genetically modified organisms (GMOs) by PCR: a brief review of methodologies available. Trends Food Sci. Technol. 9, 380–388 (1999).

    Article  Google Scholar 

  12. Anonymous Development of Methods to Identify Foods Produced by Means of Genetic Engineering EU Project SMT4-CT96-2072 (Bundesinstitut für gesundheitlichen Verbraucherschutz und Veterinärmedizin, Berlin, 1999).

    Google Scholar 

  13. Pawlowski, W. P. & Somers, D. A. Transgenic DNA integrated into the oat genome is frequently interspersed by host DNA. Proc. Natl Acad. Sci. USA 95, 12106–12110 (1998).

    Article  ADS  CAS  Google Scholar 

  14. Hartl, D. L. & Ochman, H. in Methods in Molecular Biology (ed. Harwood, A.) 293–301 (Humana, Totowa, New Jersey, 1996).

    Google Scholar 

  15. Zimmermann, A., Lüthy, L. & Pauli, U. Event specific transgene detection in Bt11 corn by quantitative PCR at the integration site. Lebensm.-Wiss. Technol. 33, 210–216 (2000).

    Article  CAS  Google Scholar 

Download references


We thank the Union de Comunidades Zapoteco Chinanteca (UZACHI) for access to their field laboratory, Y. Lara (Estudios Rurales y Asesoría, Oaxaca) for facilitation, A. King for Peruvian maize samples and CIMMYT maize germplasm bank for the historical control.

Author information

Authors and Affiliations


Corresponding author

Correspondence to Ignacio H. Chapela.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary information for Figure 2.

Sequences downstream from p-35S:

K1, 103bp identity with bp 60909-61028 of Genbank AF123535, Zea mays alcohol dehydrogenase 1 (adh1) gene (Genbank accession AF434754) .

A3, 99bp identity with bp 60918-61028 of Genbank AF123535, Zea mays alcohol dehydrogenase 1 (adh1) gene (Genbank accession AF434755).

A2, 381bp identity with bp 23403-23842 of AF090446, Zea mays cosmid IV.1E1 gag gene (Genbank accession AF434756).

A3, low scoring identity with Genbank AF023160, Zea mays starch synthase DULL1 gene (Genbank accession AF434757).

A2, 125bp identity with bp 49989-50126 of AF031569, Zea mays 22-kDa alpha zein (Genbank accession AF434758)B3, 293bp identity with bp 2402-2726 of AF050455, Zea mays gypsy/Ty3-type retrotransposon Tekay (Genbank accession AF434759).

Sequences upstream from p-35S:

K1, No significant homology with Genbank sequences (Genbank accession AF434760).

A2, No significant homology with Genbank sequences (Genbank AF434761).

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Quist, D., Chapela, I. Transgenic DNA introgressed into traditional maize landraces in Oaxaca, Mexico. Nature 414, 541–543 (2001).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:

This article is cited by


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing