Advanced genetic techniques for crop improvement: regulation, risk and precaution - Science and Technology Committee Contents

2  Genetic crop improvement: approaches and applications

Genetic crop improvement

8. Genetic crop improvement, in its broadest sense, can be defined as any process through which the genetic make-up of a plant variety or species is deliberately altered in order to increase the frequency of beneficial traits.[14] In this sense, most modern crops can be considered to be genetically improved. The intuitive use of selective breeding pre-dates our understanding of genetics and coveted traits originating in different species have also long been combined, often via artificial means such as grafting, through the process of hybridization. More recently, when breeders have wanted to increase the range of 'natural' variation available to select from, radiation has been used as a tool for doing so.[15] Such techniques were once considered cutting-edge and played an important part in the 'green revolution', during which agricultural yields increased by orders of magnitude, saving millions from starvation and drastically changing the nature of global agriculture in the process.[16] Today, however, they are more often classified as 'conventional breeding techniques', set in contrast to the 'advanced' methods that form the main subject of this report.[17]

Advanced genetic techniques

9. Genetic modification ('GM') is the term commonly used to describe a range of techniques through which plant breeders can add to, subtract from, or in some other way make more precise modifications to an organism's genetic material in order to alter existing traits or introduce new ones.[18] For decades, genetic modification has been widely used in research, medicine and other applications (see box 1) and the first genetically modified food—a tomato puree, made using the 'Flavr Savr' delayed-ripening GM tomato—was launched over 20 years ago, in 1994.[19] Since then, crops produced using genetic modification have been produced and consumed in many countries, including the US, Brazil, Argentina, Canada, India, South Africa and Spain.[20] According to the so-called 'Baulcombe report', prepared in 2014 for the Prime Minister's Council for Science and Technology, 81% of the global acreage of both soybean and cotton is currently sown to genetically modified varieties and the global acreage under all forms of GM is currently doubling every five years.[21] This amounts to 175 million hectares in total, less than 1% of which is grown in the EU.[22] However, Europe is by no means GM-free. The EU has approved more than 40 genetically modified products for import—mostly cotton, soybean and maize—and, according to the Society of Biology, "more than 70%" of the EU's protein-based animal feed is genetically modified.[23] Box 1: Other uses of advanced genetic approaches
Advanced genetic approaches have been widely used in science and industry for many years. Common applications of genetically modified organisms include:

·  Research. In 2013, over 2 million genetically modified (GM) animals—largely mice, rats and fish—were bred for research purposes.[24] These are used primarily in medical research, where they aid understanding of gene function and act as models for human disease. GM plants are also an important laboratory tool.[25]

·  Medicine. In 1982, insulin derived from modified bacteria became the first genetically engineered product to obtain approval from the US Food and Drug Administration.[26] Other therapeutic proteins, such as human growth hormone, are also now produced using GM organisms and GM plants have recently emerged as a low-cost alternative to current techniques used to produce protein-based pharmaceuticals and vaccines (this practice is known as "pharming").[27]

·  Cheese production. Since the late 1980s, GM yeast has been used to produce an enzyme called chymosin. Traditionally sourced from calf stomach, chymosin, or 'rennet', is a key ingredient in the cheese-making process. Today, about 90% of the hard cheese in the UK is made using chymosin from modified microbes.[28]

·  Environmental management. GM bacteria can be used for both the production of biodegradable plastics and for bioremediation—the use of microorganisms to remove or neutralize damaging pollutants. Several GM organisms, including plants, yeast and algae, have also been considered for use in biofuel production.[29]

10. This global market is currently dominated by a relatively small number of products which might be referred to as the 'first generation' of genetically advanced crops.


11. The 'first generation' of genetically modified products are largely transgenic: that is, they contain genetic material that originated in an organism of a different species. A variety of techniques have now been developed through which genetic material can be inserted into a target plant, but, initially, first generation methods usually led to the insertion being made at a random location in the plant genome.[30] Multiple generations of the modified crop were then grown to ensure that the gene has been properly inserted and in order to screen for any unexpected consequences.[31] First generation products typically contain one (or both) of two trait types, both of which are intended to help reduce agricultural losses from pests:

i)  Insect resistance. Bt toxin is an insecticidal chemical produced by a soil bacterium called Bacillus thuringiensis. It is poisonous to a wide range of crop pests, and chemical preparations containing Bt have been used as insecticides since the 1930s.[32] In the mid-1980s, the agricultural biotechnology industry began using advanced genetic techniques to insert the gene responsible for Bt's toxicity directly into the crop genome, seeking to confer resistance directly onto the crop and reduce the need for repeated insecticide spraying.[33] Bt-based insect-resistant crops are now produced by several companies, including Syngenta, Monsanto and Dow AgroSciences.[34]

ii)  Herbicide tolerance. Herbicides are chemicals used to kill unwanted plants. They are a special case among crop protection products because the target (the weed) and the protected crop are both plants; the challenge is to kill the weed but not the crop.[35] Advanced genetic techniques have been used to facilitate this by inserting genes that confer herbicide resistance into the crop genome, making the crop plant impervious to herbicidal spraying. Several different types of resistance have been developed using first generation techniques, the most common being tolerance to glyphosate, a widely used herbicide.[36] The most well-known collection of herbicide resistant crops are Monsanto's 'Roundup ready' products, so-named because of their tolerance to the company's popular glyphosate-based weed-killer, Roundup.

12. Evidence suggests that, like any product, insect-resistant and herbicide-tolerant crops carry potential risks as well as benefits. Constant exposure of insect pests to the Bt toxin could lead to accelerated development of resistance, reducing Bt's effectiveness over time, although evidence about whether or not this has occurred is mixed.[37] Similarly, repeated exposure of weeds to large amounts of herbicide could lead to the rapid evolution of so-called "superweeds"; a process that might be accelerated if farmers use a single herbicide more liberally as a result of growing herbicide-tolerant crops.[38] There is some evidence to suggest that crops containing Bt toxin may also pose a threat to non-target insects, such as butterflies.[39] The Royal Society argued that "where risks have been identified, for example in the case of herbicide tolerance, they relate to the trait that has been introduced rather than the method by which it was introduced".[40] It added that such effects were often the lesser of two evils, as, for example, "control of insect pests with insecticides poses a greater risk of damage to non-target organisms than control with transgenic Bt protein".[41]

13. Overall, the balance of scientific evidence, as measured by peer-reviewed scientific publications, suggests that first generation products have been effective in increasing crop yield and reducing pesticide use. A recent peer-reviewed meta-analysis of "the agronomic and economic impacts of GM crops", which looked at a total of 147 studies, found that, on average, use of these products had "reduced chemical pesticide use by 37%, increased crop yields by 22%, and increased farmer profits by 68%".[42] Yield gains and pesticide reductions were found to be larger for insect-resistant crops than for herbicide-tolerant crops, and were higher in developing countries than in developed countries.[43] Research by the US Department of Agriculture found that adoption of first generation genetically modified products in the US had correlated with a decrease in pesticide use[44] and a reduction in "the carbon footprint of agriculture".[45] The relative risks posed by genetically modified versus conventionally bred crops are discussed further in chapter 4.


14. There was some disagreement about whether or not the field of advanced crop breeding had moved on since this first generation of products was developed. Dr Doug Parr, Chief Scientist and Policy Director at Greenpeace UK, stated that things had "not changed an awful lot" over the last 20 years and Liz O'Neill, Director of the advocacy group GM Freeze, pointed out that "the crops that are currently awaiting approval in the EU are all herbicide tolerant and insecticide expressing"—in other words, they are first generation products.[46] However, Professor Sir David Baulcombe, University of Cambridge, argued that things had "moved on enormously" during this time period and claimed that "to say that things have not moved on […] is a complete travesty. It is totally wrong".[47] He explained that scientists now possessed far more genomic data and "a much more sophisticated understanding" of plant genetics, meaning that the potential to develop new technologies was now "enormous".[48]

15. The Science Council[49] agreed that a "second generation" of genetically advanced crops, displaying a wider range of traits and with much broader potential applications, had started to emerge.[50] A detailed list of traits currently "in the pipeline" was set out in the 2014 Baulcombe report[51] and, according to the Government, include:

    various forms of disease resistance (e.g. blight-resistant potatoes), various forms of abiotic-stress tolerance (e.g. drought-tolerance), nitrogen-use efficiency (i.e. enabling less use of artificial fertiliser), other forms of pest resistance (e.g. against nematodes and aphids), and crops with improved nutritional characteristics (e.g. 'golden rice', to combat vitamin A deficiency, plants that produce healthy omega-3 oils and purple tomatoes with beneficial antioxidants).[52]

Many of these traits are designed to provide consumer and environmental benefits as well as the productivity gains targeted by first generation products. Nutritionally-enhanced 'golden rice', for example, is designed to combat vitamin A deficiency and, according to the Science Council, use of GM technology in the development of an anti-malarial vaccine was further evidence of these techniques "being used for the benefit of society".[53] Much of this emerging research is being conducted in the UK (see box 2). Box 2: Genetically improved products currently under development in the UK
UK-based research has led to several potential innovations in the field of advanced genetic crop improvement. These include the following:

·  Blight-resistant potatoes. Potato blight is a rotting disease caused by a fungus-like organism called Phytophthora infestans. It was one of the major causes of the Irish potato famine and, according to the Government, costs UK farmers around £60 million each year to control through fungicidal spraying.[54] Scientists at the Sainsbury Laboratory in Norwich have used advanced genetic techniques to introduce a blight-resistance gene, common to a South American wild relative of the potato, into the popular Desiree variety in order to increase its resistance to this disease (similar work has been carried out by both BASF and Syngenta). During a period of "perfect 'blight weather'" in a recent field trial, all of the non-modified potatoes became infected with the disease, while all of the modified potatoes remained blight-free.[55]

·  Anthocyanin-enriched tomatoes. Researchers at the John Innes Institute have genetically engineered tomatoes to increase their production of anthocyanin, a natural tomato pigment. According to recent peer-reviewed research, the resulting 'purple' tomatoes demonstrated "significantly" extended shelf life, were less susceptible to a common mould and showed "increased antioxidant capacity".[56] Mice fed with high-anthocyanin tomatoes also showed a significant (30%) extension of life span.[57]

·  Omega-3 oil producing plants. Omega-3 oil is an essential fatty acid found in fish. In the wild, fish source omega-3 oil through the various algae and plankton that they consume; however, farmed fish do not have access to these dietary sources and therefore have to be fed with food artificially enriched with omega-3. This is itself sourced from wild fish populations, leading to an unsustainable depletion of fish stocks.[58] Scientists at Rothamsted Research have found a way to more sustainably produce omega-3 oils for use in fish food by inserting a genetic sequence usually found in plankton into Camelina plants, enabling the plants to accumulate omega-3 oil in their seeds.[59] A trial designed to test the effectiveness of these plants under 'real-life' conditions is currently underway.

16. While first generation products were typically transgenic and involved genetic material being randomly inserted into the plant genome, second generation products are increasingly using more subtle and precise techniques. These include:

·  cisgenic modification, in which the inserted gene is derived from the same species as the target plant (for example, as in the blight-resistant potatoes described in box 2);

·  genome editing, through which insertions, deletions and other modifications—sometimes of extremely short sections of DNA—can be targeted at specific sites in the plant genome, and

·  epigenetic modification, through which specific genes can be selectively 'silenced' without directly changing the underlying genetic sequence.[60]

According to Professor Rosemary Hails, Chair of the Advisory Committee on Releases to the Environment, unlike first generation techniques, "these new techniques are about moving genes between species that are sexually compatible, altering the configuration or even just making a point change".[61] She added: "they have filled in all of the grey space between conventional breeding and recombinant DNA technology".[62] Professor David Baulcombe, University of Cambridge, explained that advances in genome sequencing technology also meant that it was now "relatively easy to characterize the complete genome sequence and the transgene insertion sites in the recipient genome", further reducing uncertainty about the potential impact of the process.[63]


17. A recurring theme of this inquiry has been the importance of terminology and the inadequacy of the shorthand term 'GM' as a label for the various techniques and applications described above. As Professor Sir Mark Walport, the Government Chief Scientific Adviser, recognised, this overly simple terminology encourages us to "talk about this as though it was a generic technology, which we should not do".[64] He explained:

    Whether GM technology is a good or bad thing is not a sensible question; it depends on how it is applied. The question in every case is: what gene, what organism and for what purpose?[65]

Under EU legislation, a genetically modified organism is any organism, "with the exception of human beings, in which the genetic material has been altered in a way that does not occur naturally by mating and/or natural recombination".[66] This broad definition could be considered to include some of the emerging techniques described above; however, the term 'GM' was coined at a time when transgenic insertion was the dominant technique and insect and herbicide resistance were the dominant traits. The term is therefore closely associated with these first generation products.

18. The term genetic modification, or GM, is most commonly used to describe a transgenic process in which a gene from one organism is inserted, often at random, into the genome of another organism of a different species. This fails to accurately portray the wide range of techniques through which targeted genetic changes can now be introduced into crops, which include same species cisgenic transfers, precise point changes to the plant genome and epigenetic modifications that do not alter the underlying genetic sequence. In our view, it is time to update this imprecise and problematic terminology.

19. We recognise that the term GM has become embedded in everyday language and is now often used imprecisely to encompass a whole range of technologies. In this report—except when quoting from evidence or using legally significant terminology—we will attempt to avoid using the term 'GM' and will use the phrase 'genetic modification' only when referring specifically to the first generation transgenic techniques to which it has historically been applied. We will avoid this terminology when referring more broadly to the full range of advanced genetic techniques currently in development. We recommend that the Government initiate a reframing of the public conversation by similarly moving away from the overly simple notion of 'GM' in its own policies and communications. This matter is discussed further in chapter 6.

14   This definition derives from a 2014 position statement issued by the Biotechnology and Biological Sciences Research Council (BBSRC). This used the term 'genetic crop improvement' to describe a range of methods that relied on "introducing genetic changes" in order to "add beneficial characteristics or remove undesirable ones". See Biotechnology and Biological Sciences Research Council, New techniques for genetic crop improvement: position statement, September 2014, accessed 26 January 2015. Back

15   Noel Kingsbury, Hybrid: The history and science of plant breeding, (Chicago, 2009), pp.163-165; pp.267-268. Back

16   Noel Kingsbury, Hybrid: The history and science of plant breeding, (Chicago, 2009), pp.285-328 Back

17   For an example of this type of distinction, see Nuffield Council on Bioethics, Genetically modified crops: the ethical and social issues, May 1999, chapter 2. Back

18   Based on: Richard Cammack et al (eds.), Oxford Dictionary of Biochemistry and Molecular Biology, 'Genetically modified organism', 2nd edition, 2008, Oxford Reference Online, accessed 26 January 2015. Back

19   GMC055 [IGD]  Back

20   David Baulcombe, Jim Dunwell, Jonathan Jones, John Pickett and Pere Puigdomenech, GM science update: a report to the Council for Science and Technology, March 2014, p.9 Back

21   David Baulcombe, Jim Dunwell, Jonathan Jones, John Pickett and Pere Puigdomenech, GM science update: a report to the Council for Science and Technology, March 2014, p.1 Back

22   In the EU, only one GM product is currently grown commercially: an insect resistant variety of GM maize, approximately 100,000 hectares of which is grown in Spain. This accounts for around 30% of Spain's total maize production. GMC029 [SCIMAC] para 34 Back

23   GMC046 [Society of Biology] para 4 Back

24   Home Office, Annual Statistics of Scientific Procedures on Living Animals: Great Britain 2013, HC 372, 10 July 2014, p 17. Back

25   Biotechnology and Biological Sciences Research Council, correspondence to Andrew Miller MP,, April 2014. Back

26   US FDA, Celebrating a Milestone: FDA's Approval of First Genetically-Engineered Product, 2007, accessed 8 December 2014.  Back

27   Parliamentary Office of Science and Technology, Plant-made pharmaceuticals, POSTnote 424, December 2012. Back

28   University of Reading, National Centre for Biotechnology Education, Case studies: chymosin, accessed 8 December 2014. Back

29   See, for example, Parliamentary Office of Science and Technology, Biofuels from algae, POSTnote 384, July 2011. Back

30   Nuffield Council on Bioethics, Genetically modified crops: the ethical and social issues, May 1999, para 2.7. Back

31   This type of insertion technique is described at: Food Standards Agency, 'GM basics: how does genetic modification work?',, accessed 26 January 2015. See also Q15 [Dr Parr] Back

32   The Royal Society, Reaping the benefits, October 2009, case study 3.1, p.23 Back

33   The Royal Society, Reaping the benefits, October 2009, case study 3.1, p.23 Back

34   See the EU register of authorised GMOs,, accessed 26 January 2015. Back

35   The Royal Society, Reaping the benefits, October 2009, p.30 Back

36   The Royal Society, Reaping the benefits, October 2009, p.30 Back

37   GMC041 [Wildlife and Countryside Link] para 4.4. According to the US Department of Agriculture, "so far, the emergence of insect resistance to Bt crops has been low and of 'little economic and agronomic significance', but there are some indications that insect resistance is developing to some Bt traits in some areas". US Department of Agriculture Economic Research Service, Genetically Engineered Crops in the United States, Economic Research Report Number 162. February 2014, pp.29-31. Back

38   The Royal Society, Reaping the benefits, October 2009, p.30. See also GMC024 [Mr Kevin R Coleman] para 12; GMC018 [Dr Richard Weightman] para 8; Q21 [Ms O'Neill]; Q117 [Mr Melchett]; US Department of Agriculture Economic Research Service, Genetically Engineered Crops in the United States, Economic Research Report Number 162. February 2014, pp.31-33. Back

39   Q337 [Professor Perry]; Q21 [Ms O'Neill]. Note, according to the Royal Society: "Some laboratory tests seemed to indicate that the pollen of Bt maize presents a threat to monarch butterflies. However, further studies showed that Bt maize pollen did not in fact pose a threat as the density of pollen on the milkweed leaves on which monarch caterpillars feed is much lower than that which would cause harm". The Royal Society, Reaping the benefits, October 2009, case study 3.1, p.23 Back

40   GMC044 [Royal Society] para21. See also Q22 [Professor Leyser]; GMC037 [Agriculture and Horticulture Development Board] para 9 Back

41   The Royal Society, Reaping the benefits, October 2009, p.23, p.30. The US Department of Agriculture similarly stated that glyphosate, "the most heavily used pesticide in the United States since 2001", in part because of high take-up of genetically modified glyphosate-resistant crops, "is more environmentally benign than the herbicides that it replaces". US Department of Agriculture Economic Research Service, Genetically Engineered Crops in the United States, Economic Research Report Number 162. February 2014, p.31. Back

42   Wilhelm Klümper and Matin Qaim, "A Meta-Analysis of the Impacts of Genetically Modified Crops", PLOSOne, November 3 2014. DOI: 10.1371/journal.pone.0111629. Back

43   Wilhelm Klümper and Matin Qaim, "A Meta-Analysis of the Impacts of Genetically Modified Crops", PLOSOne, November 3 2014. DOI: 10.1371/journal.pone.0111629. Back

44   The report concluded that while "insecticide use decreases with the adoption of Bt [insect resistant] crops", adoption of herbicide-tolerant [HT] crops had a "mixed but relatively minor effect" on herbicide usage. It added that "the main effect of HT crop adoption on herbicide use is the substitution of glyphosate for more toxic herbicides", leading to "an improvement in environmental quality and a reduction in the health risks associated with herbicide use". See US Department of Agriculture Economic Research Service, Genetically Engineered Crops in the United States, Economic Research Report Number 162. February 2014, pp.23-26. Back

45   US Department of Agriculture Economic Research Service, Genetically Engineered Crops in the United States, Economic Research Report Number 162. February 2014, pp.26-27. Back

46   Q4 [Dr Parr]; Q26 [Ms O'Neill] Back

47   Q35 Back

48   Q35 Back

49   The Science Council is an umbrella organisation representing 41 UK learned societies and professional bodies. Back

50   GMC047 [Science Council] para 2.4. See also GMC009 [James Hutton Institute] para 2 for use of this terminology. Back

51   David Baulcombe, Jim Dunwell, Jonathan Jones, John Pickett and Pere Puigdomenech, GM science update: a report to the Council for Science and Technology, March 2014, pp.16-19. These included enhanced photosynthesis, stress tolerance, aluminium tolerance, salinity tolerance, pest and disease resistance, nitrogen and phosphorus use efficiency and nitrogen fixing. Back

52   GMC051 [Gov] para 15 Back

53   GMC047 [Science Council] para 2.5 Back

54   GMC051 [Gov] para 12; Jim Donnelly, The Irish Famine, BBC History, February 2011, accessed 9 December 2014. Back

55   Jonathan D. G. Jones, Kamil Witek, Walter Verweij, Florian Jupe et al, Elevating crop disease resistance with cloned genes, Philosophical Transactions of the Royal Society B, vol 370 (2014) DOI: 10.1098/rstb.2013.0087 Back

56   Yang Zhang, Eugenio Butelli, Rosalba De Stefano, Henk-jan Schoonbeek. et al, Anthocyanins Double the Shelf Life of Tomatoes by Delaying Overripening and Reducing Susceptibility to Gray Mold, Current Biology, vol 23 (2013) DOI:10.1016/j.cub.2013.04.072 Back

57   Eugenio Butelli, Lucilla Titta, Marco Giorgio, Hans-Peter Mock et al, Enrichment of tomato fruit with health-promoting anthocyanins by expression of select transcription factors, Nature Biotechnology, vol 26 (2008). DOI.10.1038/nbt.1506. Back

58   GMC015 [Sense about Science] Appendix 1 Back

59   Rothamsted Research, Questions and answers, accessed 9 December 2014. Back

60   Further information on these techniques is available at: Biotechnology and Biological Sciences Research Council, New techniques for genetic crop improvement: position statement, September 2014; Advisory Committee on Releases to the Environment, ACRE advice: New techniques used in plant breeding, July 2014. Back

61   Q427 Back

62   Q427 Back

63   GMC027 [Professor Baulcombe] para 8 Back

64   Q273 Back

65   Q273 Back

66   Directive 2001/18/EC of the European Parliament and of the Council of 12 March 2001 on the deliberate release into the environment of genetically modified organisms, article 2 (2) Back

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