GM debate crops up again

Thirty years ago this month, scientists introduced a foreign gene into plant cells for the first time. Genetically modified (GM) plant technology was born. But, almost 20 years after the research was first used commercially, no GM crops are sold in the UK. Indeed, the use of GM plants is strictly regulated throughout the EU.  This is in stark contrast to other developed countries such as the USA, Canada and China, where the supply of staples such as maize, cotton and soya beans now comes predominantly from GM plants. So why has the UK been so slow to follow in the footsteps of other global powers?

One of the reasons that Britain is reluctant to embrace GM crops may be the lack of rational, reasoned debate around the issue. Terms such as ‘Frankenfoods’, coined by a scaremongering media, elicit strong emotional responses. This gut feeling that something is unnatural about GM often overrides the scientific debate about the benefits and dangers of growing GM crops. This is not helped by the fact that those campaigning for GM foods are often those who stand to gain; biotechnology companies. In short, in the UK, we think GM foods are icky.

So what are the legitimate pros and cons of GM plants?  Should the UK get over its squeamishness towards GM and accept that genetically engineered food is the future, a way to feed the world as its population rapidly expands?  There  are many economic and social issues often raised when discussing GM, for example the morality of allowing developing countries to become reliant on big business for their food source. I don’t have the time or depth of knowledge to discuss these issues here, although if your interested this report covers them in depth. Instead, let’s look in brief at two of the scientific issues that seem to most concern the general public in the UK. Firstly, could the genetically modified plants spread and contaminate other plants, damaging our ecosystem and posing a risk to our health?  Secondly, why do we need GM crops in the first place?

Rothamsted Research, an agricultural research institute in Hertfordshire, is currently performing trials on a strain of GM wheat that has been genetically altered with the aim of conferring protection against aphids. A gene from a mint plant has been inserted into the wheat genome, which enables the plant to produce a pheromone called (E)-β-farnesene.  This acts as a two-pronged aphid ‘alarm bell’, which not only sends signals to aphids telling them that danger is close at hand, sending them fleeing, but also attracts aphid predators such as ladybirds to the area. In theory, this approach should allow a decreased use of pesticides.  This is beneficial as pesticides are both environmentally damaging and implicated in the emergence of new ‘super’ strains of pesticide-resistant aphid. Rothamsted categorically state that appropriate safeguards have been put in place to ensure that there is a negligible risk of cross-contamination between the GM wheat and any neighbouring farms. These assurances, however, have not satisfied GM sceptics.

Headed by anti-GM campaign group Take The Flour Back, environmental activists last year attempted (unsuccessfully) to destroy the GM wheat being tested at Rothamsted. Despite the best efforts of the researchers, TTFB’s biggest concern remains the risk of cross-contamination. The scientists in charge of the project rightly point out that wheat is self-pollinating, rather than being fertilised by pollen carried on the wind or by insects. Any escaping pollen is therefore unlikely to find its way into another plant.  What’s more, wheat pollen is heavy, and tends to fall to the ground rather than be blown into the air.  In addition, Rothamsted havs ensured that a wide perimeter is in place around the wheat and has installed a pollen-catching barrier.

Nonetheless, a ‘negligible’ risk is still too big a risk to take for those that argue that GM is unnecessary. If the risk is very low, but the outputs of GM produce are high, the argument goes, eventually some GM DNA will escape into the ‘wild’.

This argument may well be sound. There is some evidence, albeit sketchy, that foreign genetic material from GM plants may have found its way into native crops in certain situations. In Mexico, some of the genetic material used to turn on the foreign genes was found in supposedly natural maize fields.  However, the experiments were criticized as flawed by other scientists within the field. Subsequent experiments have not always found traces of GM material. In the USA, GM giant Bayer was found to be responsible for allowing GM rice to cross-contaminate traditional long-grain rice.

Rothamsted argue that GM wheat is a different case. But, rather than try and convince a sceptical crowd that nothing can possibly go wrong, they might do better to address the issue of what would happen if cross-contamination did occur. In the USA, cross-contamination of the rice has not had any long-term affects on the viability of the natural crops. Furthermore, fears that GM contamination can pose health risks are unfounded. These foreign genes will not harm the unwitting consumer, as they have already been approved as safe to eat. Finally, it pays to remember that civilisation has conducted a more primitive version of genetic engineering over many centuries. By deliberately breeding crops that have appealing traits, such as higher production rates, longer flowering seasons or improved tolerance to inclement temperatures, we have altered the genetic makeup of the plants that we cultivate over time to maximise the benefits to ourselves.  GM technology is in many ways a natural next step in our history of genetic manipulation.

The waters around GM cross-contamination worries remain murky for now. There are many variables which even experts within the GM field do not yet fully understand. The simple truth is that without large scale trials and long-term testing we do not know what the full impact of cross-contamination will be.  It is perhaps not surprising, then, that despite the evidence indicating that GM is not harmful when used properly, the public remain resistant. If these crops are unwanted, why do scientists continue to pursue this line of research? Are GM crops necessary?

GM crops on the market at the present time typically either allow the plant to grow in the presence of herbicides or pesticides. Critics who reject the claims that these crops reduce the impact of intensive farming on the environment assert that the benefits of these types of modification are primarily monetary, benefitting the biotech companies who produce the seeds. But a new generation of GM plants are currently undergoing trials, of which the benefits to the developing world promise to be much greater.

Golden rice is probably the most famous example of this new breed of crops. The rice is genetically modified to produce up to 35micrograms of vitamin A in each grain. The researchers leading trials in the Philippines hope that the GM crop could save large numbers of the 6000 people who die from vitamin A deficiency every day. Despite the obvious benefits of this type of GM food, production of the rice for human consumption has still to be approved. In a letter to Nature (behind a paywall) in 2010, one of the researchers leading the project expressed his frustration at the obstacles placed in the way of bringing GM crops to market, and stated that the stalling had cost the lives of thousands of children.

Another example is Cassava, a tuber that is a staple of the diet in many parts of Africa. Cassava is blighted by two prevalent viral diseases, and while some strains are resistant to one disease or the other, no naturally occurring strains are resistant to both.  Using genetic engineering, scientists are now trying to insert genes from one resistant strain into another, to produce crops that can resist either virus. This plant has the potential to improve the lives of farmers throughout Africa, and put regular food on the table in developing countries.

Whatever decision each person in Britain makes about the food they eat and feed to their families, amidst all the debate it’s important to keep sight of one of the initial goals of GM; the dream of feeding the world. Whilst consumers in the UK have the freedom to be selective about the foods they are willing to make a part of their diets, millions of people in developing countries have no such choice.  The GM crops currently undergoing testing stand to transform nutrition in such countries. If these crops eventually get the go-ahead from regulatory boards, we must learn to swallow our squeamishness and accept that there are shades of grey in all things. Where malnutrition is the alternative, GM must be considered as a viable option.

Elsewhere on the web…

This blog entry was inspired by a special edition of the journal Nature, in which several articles attempted to dissect the middle ground of the GM arguments.  Many of the articles are free to access, and make for interesting reading.

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