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How can we be sure that longer term effects which cannot yet be detected, like recidivism/regression (loss of beneficial traits), or unexpected nth-generation mutation (either due to de-stabilised genetics, or wider environment influences such as other plants or organisms) dont happen 20 or 30 years down the line? (the key point not being the specific time-frame offered, but that it's longer than the period to get the organisms approved for release). Is it the case that its inferred anything a decade or more down-the-line is simply too unpredictable to care about? Do the lab studies include a range of soil types and environmental conditions, and how per-patented seed would this information be accessed and feedback be accessed from the public, other scientists?

Submitted by: Lewis Cowles


Answer

Expert response from Peter J. Davies

Professor of Plant Physiology and International Professor of Plant Biology, Cornell University, Ithaca New York, USA

Friday, 12/04/2019 20:24

When a gene for a desirable characteristic is inserted into a plant genome only a small percentage of the transformations express the desired trait with no other discernable effects. Undesirable products can be due to unsuccessful insertion or insertion in an inappropriate location in the genome. The selected plants undergo further examination in the laboratory, greenhouse and in extensive field trials to ensure the satisfactory performance for the expression of the trait and agronomic characteristics, and for safety. Should the trait be unstable this would be detected during trials. In addition, we now have 20 years of experience in the growing of crops with the major genetically engineered traits, namely insect and herbicide resistance, with no notable loss of the characteristic or breakdown in crop performance, and with no concerns about safety[1] .

 

When a gene sequence is inserted through genetic engineering there may be other changes in the genome. However, this is no different from changes that may also occur during conventional breeding[2]; indeed one recent paper claimed that gene insertion via genetic engineering caused less change in the maize genome than traditional breeding![3] Radiation breeding (via the exposure of plants to atomic radiation) produces even more extreme changes throughout the genome, and yet that has been used to produce many subsequently stable plant varieties (3284 as of February 2019).[4] The genome is not static, especially during the production of gametes in reproduction. In addition, some genes called transposons or “jumping genes” move around and can change some characteristics, but this is no different in genetically engineered crops than in traditionally-bred crops, and if a gene is inserted in an unstable position, it will be detected and the plant removed from further development. If the characteristics of the progeny crop are stable during trials, and especially after years of use, there is no reason to expect a sudden change in the future. This is not to say that a change is impossible, as science never considers anything as absolutely certain, but it is extremely unlikely. Any occasional mutations or gene movement in individual plants will be no different from that of conventionally bred crops, and we do not express any concerns about such conventionally-bred crops. I do not consider that stability is unpredictable: the prediction is that overall there will be no significant changes of relevance.

 

I have included several technical references below where this topic is discussed in detail.

 

[1] See https://geneticliteracyproject.org/2017/05/19/activists-claim-without-long-term-studies-gmos-cannot-considered-safe-science-say/

[1] Weber N, Halpin C, Hannah LC, Jez JM, Kough J, Parrott W, (2012) Crop genome plasticity and its relevance to food and feed safety of genetically engineered breeding stacks. Plant Physiol 160:1842–1853. www.plantphysiol.org/cgi/doi/10.1104/pp.112.204271

Schnell, J. et al. (2015) A comparative analysis of insertional effects in genetically engineered plants: considerations for pre-market assessments. Transgenic Res 24:1–17. https://doi.org/10.1007/s11248-014-9843-7

[1]See https://doi.org/10.1111/pbi.12713 summarized in http://www.isaaa.org/kc/cropbiotechupdate/article/default.asp?ID=15366

[1] https://mvd.iaea.org/

 

[2] Weber N, Halpin C, Hannah LC, Jez JM, Kough J, Parrott W, (2012) Crop genome plasticity and its relevance to food and feed safety of genetically engineered breeding stacks. Plant Physiol 160:1842–1853. www.plantphysiol.org/cgi/doi/10.1104/pp.112.204271

Schnell, J. et al. (2015) A comparative analysis of insertional effects in genetically engineered plants: considerations for pre-market assessments. Transgenic Res 24:1–17. https://doi.org/10.1007/s11248-014-9843-7