Andy Stirling answered on 4 Jul 2012:
This question from ‘Jetgirl’ gets to the nub of an important dilemma around GM foods. The safety and environmental issues that we’re discussing in this Forum certainly would be somewhat addressed – at least in part – by rendering the crops in question incapable of reproducing. This would not reduce any direct effects. But (if the measures worked as intended) they would somewhat mitigate indirect effects consequent to the crops further propagating themselves.
To the extent that the adverse effects in question are specific to GM crops, then it follows that these measures could have a correspondingly positive contribution to make in GM regulation. And I have noted in another answer how – despite claims to the contrary by some GM proponents – there are indeed some very particular food risk management issues, that are incontrovertibly specific to GM crops. These particular issues are around the management of potential risks from possible sensitisers or allergens that might (as does sometimes happen) escape regulatory screening. These are more easily avoided in non-GM foods.
So, the dilemma is – exactly as jetgirl says – that this measure that might be helpful in environmental or safety terms, is potentially highly problematic in agronomic and livelihood terms. This is because rendering crops infertile reduces the options for farmers, of being able to share seed or selectively breed from among their own crops. This practice is especially problematic for poorer farmers and those farming in conditions that are not directly addressed by industrially-produced crops.
So, this is indeed a significant issue, that is to some extent particular to GM crops. It does not apply to open source, participatory plant breeding techniques. These do not so strongly force a choice of this kind, because they do not pose the specific issues raised above. And these non-GM techniques are in any case deliberately designed to allow the maximum flexibility in use by farmers.
Les Firbank answered on 6 Jul 2012:
I disagree with Andy, I don’t think this is an important dilemma, as long as farmers get clear choices.
This situation is not as new as it sounds. Many of the more productive crops are ‘hybrid’ varieties, that lose their hybrid vigour and consistency if the seeds are are taken from the crop plans and sown the following year. In this case, farmers buy the seeds every year, because the benefits outweigh the costs. Different farmers have different needs, and different ways of making money.
Crops with infertile seeds may be useful for some farmers, because one of the problems with many crops is that seeds can fall off the crop and grow the following year, and for some crops (like oilseed rape) for several years afterwards. Such unwanted crop plants are called ‘volunteers’ and can be hard to control; using infertile seeds solves that problem.
Whether infertile seeds solves the problem of “contamination” depends on how big the problem really is.
Ricarda Steinbrecher answered on 13 Jul 2012:
Infertile or sterile GM seeds are commonly referred to as Terminator Technology –
technically also known as V-GURTs (genetic use restriction technologies). They are specific and complex GM technologies designed to either render seeds sterile at harvest or to prevent saved seeds from growing into mature plants by disrupting plant development at various stages. This is done by making the plant produce a cell-toxin that will become active at a certain developmental stage and kill for example the seed embryo or the sprouting plant.
This technology was first granted a patent in the US in 1998 as a ‘technology protection system’ to stop farmers from saving and growing seeds of patented crops, triggering a global outcry. ‘Infertile seeds’ would make farmers dependent on seed companies. Not to be able to save and replant seeds blocks self-sufficiency and independence and hinders farmers from developing local varieties adapted to local conditions, which requires that seed is grown and harvested in the same region for several plant generations. Farmers would also be at risk of losing their own locally-adapted varieties.
Later terminator technology was (and continues to be) put forward as a containment strategy for GM crops; this has not been based on solid facts and actual data but rather as a conceptual proposal.
Just to recall: any biological containment system setting out to prevent gene flow of transgenes via pollen and seed must be 100% reliable and effective – otherwise it is not a containment system!
Intrinsic to their design, pollen from V-GURTs plants is fertile and thus can and do contaminate crops on other fields (via wind and pollinating insects). The resulting seeds would be sterile if the technology would work to plan. It would be a threat to food security and food sovereignty if farmers unknowingly kept and sowed such sterile seeds in the next season.
The technology is still at the development stage. Scientific articles have been published about components of transgenic switch mechanisms, but not on fully functioning V-GURTs plants. However, these articles already indicate that V-GURTs will not offer a fully reliable system to prevent contamination of GM crops and GM foods, as the individual components already do not work reliably (for more info see below ). A percentage of seeds presumed to be sterile will be fertile (leading to gene flow) and a percentage of seeds treated so as to be fertile will be sterile (leading to yield loss).
Hence farmers, whose crops have been contaminated through cross-pollination and who save their own seeds would have a percentage of GM seed that would grow despite being designed to be sterile. This would allow for the spread of the GM trait(s) which had been placed into the plant in the first place, whether that was herbicide tolerance, production of insecticidal proteins (eg Bt) or production of pharmaceuticals.
Some may turn to terminator technology in the hope to find a solution. Yet if they do not understand the science they may be inclined to believe that sterile seed technology can prevent gene escape and contamination. And it is this, which may actually lead to further spread and contamination. After all, the technology was originally designed and patented as a “technology protection system”, where a reliability and efficiency of 70% may already be sufficient to prevent farmers from saving seed. But as a containment system, 100% are required.
Due to the risks and the threat to food security and biodiversity, a de facto global moratorium is in place against terminator plants, which was passed by the UN Convention on Biological Diversity in 2000.
– – – – – – – – –
 V-GURTs is likely to only be as good as its weakest link. There are a number of known events which can interfere with reliable performance of any of the components employed by this GM technology, including: Gene Silencing and epigenetic changes to DNA, mutations, loss of promoter activity, leaking promoter systems, insufficient induction of promoter systems by inducing agent, unspecific or unintended induction of promoter system, segregation of the different genetic components during reproduction. [For more detailed explanation see Steinbrecher 2006, 2005]
If you are interested in further materials, please have a look at
Steinbrecher RA (2006). V-GURTs (Terminator Technology): Design, Reality and Inherent Risks. Report by Econexus and the Federation of German Scientists, prepared for the Convention on Biological Diversity, Working Group on article 8(j). Official Information Document UNEP/CBD/WG8J/4/INF/17. Report available from http://www.econexus.info/publication/v-gurts-terminator-technology
Steinbrecher RA (2005). V-GURTs (Terminator): Can it be effective as a containment tool? Briefing available at: http://www.econexus.info/publication/v-gurts-terminator
Steinbrecher RA and Mooney PR (1998). Terminator Technology – The Threat to World Food Security.
The Ecologist, 28(5):276-279
A version without the Boxes and Figures can be found at: http://www.econexus.info/publication/terminator-technology
For information produced by the ETC Group on Terminator Technology please see: http://www.etcgroup.org/node/634
As nothing in science is 100% certain, what steps can be taken to gather high quality evidence of effectiveness (or
My main worry about GM is that modified genes could leak or escape into non-GM species with unpredictable and possibly
Given that many plant species are capable of propagating - without human intervention - over substantial distances