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Analysis of Primary Biotechnology Literature

Analysis of Primary Biotechnology Literature. Biotechnology Education Forum NDSU Extension Inservice Training Bismarck, ND March 1, 2002. Phil McClean Department of Plant Science North Dakota State University. Concerns for Biotech Products: Ecological Balance Will Be Altered.

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Analysis of Primary Biotechnology Literature

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  1. Analysis of Primary Biotechnology Literature Biotechnology Education Forum NDSU Extension Inservice Training Bismarck, ND March 1, 2002 Phil McClean Department of Plant Science North Dakota State University

  2. Concerns for Biotech Products: Ecological Balance Will Be Altered • Other organisms will be affected • Monarch butterfly • Maize Bt pollen falls on neighboring milkweed • Milkweed a monarch butterfly food source • Does the pollen affect the butterfly • Losey et al. (1999) Nature 399:214 • Yes!! • Sears et al. (2001) PNAS 98:11937 • No!!

  3. Concerns for Biotech Products: Inadvertent Gene Transfer • Wild relatives receive transgene from biotech crops • Important genetic diversity will be lost • Has it been observed? • Quist & Chapela (2001) Nature 414:541 • Yes!! • Has it been challenged? • Christou (2002) Transgenic Research 11:iii • Yes!!

  4. Let’s Review the Primary Literature Transgenic DNA Introgressed Into Traditional Maize Landraces in Oaxaca, Mexico David Quist and Ignacio Chapela Nature 414:541-543 November 29, 2001

  5. What does the title tell us?

  6. What does the title tell us? Transgenes were found in landraces

  7. What does the title tell us? Transgenes were found in landraces What does this imply?

  8. What does the title tell us? Transgenes were found in landraces What does this imply? Biotech crops have contaminated nature

  9. Paragraph 1: What was analyzed?

  10. Paragraph 1: What was analyzed? • Bulk seed from corn cobs from landraces • Fields isolated from roads • Six samples (A1-A3 and B1-B3) • Store sample (K1) • Controls • Peruvian sample (P1) • Oaxacan sample from 1971 (H1) • Monsanto “Yieldgard” maize (Bt1) • Monsanto “Roundup-Ready maize (RR1)

  11. Paragraph 1: How were samples analyzed?

  12. Paragraph 1: How were samples analyzed? • DNA isolated from flour • Scored for presence of 35S promoter • Why??? • Widely used transgene contruct element • Polymerase chain reaction technique • Presence of product = • transgene promoter DNA is in sample

  13. Paragraph 2: What are the results?

  14. Paragraph 2: What are the results? • Amplification observed in 5/7 samples • Weak, but present • Low copy # gave low signal • Store sample gave strong signal • Bt1 and RR1 gave strong signal • Historical and Peruvian samples negative • Positive control amplification observed in all samples

  15. Paragraph 2: Supporting evidence?

  16. Paragraph 2: Supporting evidence? • Independent confirmation by Mexican gov’t • Oaxaca and one other state • Samples near authors site also positive at low levels • Mexican experiment analyzed individual kernels • Strong signal than pooled samples authors used

  17. Paragraph 3: Confirming Experiment?

  18. Paragraph 3: Confirming Experiment? • Weak signal amplified with internal primers • New fragment sequenced • Sequence equal Monsanto 35S promoter sequence

  19. Paragraph 4: Other genes present?

  20. Paragraph 4: Other genes present? • Samples asssayed for other transgenes • NOS terminator sequence • A3, B2 and K1 • Bt toxin gene (cryIAb) • B3 • Conclusion: • Multiple transgenes found in the Mexican landraces

  21. Paragraph 5: Clues to transgene origin?

  22. Paragraph 5: Clues to transgene origin? • Samples assayed for genomic location of transgene • Procedure: Inverse PCR • Scores transgene and neighboring maize DNA • Four samples contain known flanking genes • A2, A3, B3, K1 • Transgene located in same position as Novartis Bt11 • Samples A3, K1 • Conclusion: • GMOs to landraces introgression occurring • Despite GMO planting in Mexico (1998-now)

  23. The Challenge to Quist & Chapela • Chistou (2002) • Fundamental flaws (experimental design) in research • Results can be explained by: • Contaminated samples • Flawed iPCR interpretation • Cross pollination not supported by results • Better experiment • Grow plant samples out and: • Score phenotype (Bt or Glyphosate tolerant) • Score genotype (screening individual plants)

  24. What’s Next?? • Funding becomes available • Detailed experiments • New results or interpretation • What’s at stake? • Integrity of biotech approaches to crop improvement

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