Topic 1 - Genetic modification

Question 1

What are the 3 broad concerns or worry that GM products might be detrimental to human health?

Answer 1

There are at least three broad and overlapping areas of concern about GM crops. First, there is the very significant worry that GM products might be detrimental to human health. This includes concerns that:

The use of antibiotic marker genes might increase bacterial resistance to antibiotics.

New proteins manufactured in GM crops might provoke unwanted allergic responses.

Novel combinations of genes might have longer-term human health effects of an uncertain nature and severity.

Question 2

Give some examples of potential environmental effects that crops have on the environment?

Answer 2

Second, there are concerns over potential environmental effects. Examples may include the following:

Insect-resistant crops may adversely affect benign insect species (so-called non-target species).

The adoption of herbicide-tolerant crops might encourage farmers to use greater quantities of broad-spectrum (non-specific) herbicides, with resulting detrimental effects on wildlife.

Genes might spread from the crop plant to wild relatives, to produce herbicide-tolerant weeds that are far more difficult to control; or insect-resistant weeds, which might affect a much wider number of non-target species.

Question 3

Give some examples of broad political concerns of GM crops?

Answer 3

Third, there are a number of broadly political concerns. For example, there is the anxiety that GM crops are only one step further in the industrialisation of agriculture. By this logic, it could be that much of the dislike of GM crops stems from guilt by association; they are produced by agrochemical and seed companies and they are an element of ‘non-traditional’ farming. There are also real concerns about the level of economic control these large, frequently multinational, companies would have over our food systems if farmers worldwide became reliant on GM crop varieties.

Question 4

What does peer review mean?

Answer 4

Peer review is the crucially important process at the heart of communication within the scientific community. Scientists submit research papers to scientific journals; the journals then recruit anonymous experts in the same field to thoroughly check the work before it is published.

Question 5

The following card will inform you of different types of ways of communicating with the public.

Now think about the three items you read and watched. What strikes you about the style of communication, the approach taken to explain the issues, or the use of scientific evidence to back up any specific scientific claims made? Make some notes in the response box below to address these issues.

Answer 5

In Video 1.1, Shiva deliberately uses emotive language to tap into potential listeners’ existing concerns. It is clear that she has strongly held views on the issues and it is obvious what these are. In this context there is little attempt to back up statements with facts and where facts are given they are not corroborated (the source given). This is entirely appropriate for the role her video plays on a campaigning website, but it is not an impartial source of information. The language used is simple and accessible to all.
In the opinion piece in The Conversation the two authors use journalistic language to refute specific claims made by anti-GM campaigners (and Shiva in particular). The language used is reasonably accessible. Here too there is a clear sense of the authors’ opinions as pro-GM supporters and there is a feeling of a ‘campaign’ where the authors attempt to influence readers’ opinions. There is a greater amount of scientific fact (than in Shiva’s video) presented and this is referenced to other printed articles, which can be checked by the reader.
The piece in Nature is also written with a journalistic style but with a more specialist audience in mind. Although still accessible to the interested public, it is a tougher read than the other pieces. It is referenced to other journal articles and to some original peer-reviewed scientific papers and it includes specific data from reliable sources. The article in general presents argument from both sides of the GM debate on three key issues and draws on evidence. It tends to point out that conclusions on certain issues are not clear-cut where evidence is lacking.

Question 6

Next is a card following my response on what i think of GMO crops?

Answer 6

1 Concerns about GM crops
Note down your opinions on GM in general here. You might like to revisit these notes when you have completed this week’s study.

Your response:
I can understand the reasons behind GMO crops and the need to do it. I feel it would only be an option for the wealthy farmer as you would need the funds to invest in the crops initially and keep on top of the herbicide products. There must be the gain to the farmer in terms of profit otherwise they wouldn’t do it. This means that the smaller farms would have to sell their crops for less if the bigger industrial farms are producing alot. The crops that contain pesticide is beneficial to the environement as it means less pesticides is put in to the environment. I would be against it because its not something that I would want to put in to my body and the full effects on the body are not yet understood. Forcing genetics into crops is not natural and surely this would affect the person or animal consuming it. People in third world countries would not benefit from this and would actually be at a disadvantage because they would also have to sell their crops for less. Although the idea is to feed more people it is not feeding the people that need it.
By applying lots of herbicide to herbicide resistant plants super weeds are created much quicker than what would happen naturally, so more herbicide needs to be used which costs more money, smaller farmers and poor countries will not benefit from this.

Question 7

Suppose that a disease-resistant rice plant could be obtained either ‘naturally’ – i.e. via conventional plant breeding – or via the ‘engineered’ route. Which would be more acceptable to you and why?

Answer 7

Your answer might be one or the other, both, or neither. This is not a question anyone else can answer for you. However, do make sure you have written down the reasons underpinning your choice; it will be useful to come back to them later on. Do you think your choice is based on logic or feelings?

I would say naturally because I feel this is made to its purest form without any intervention but if the chemical components are exactly the same engineered then there is probably no difference.

Question 8

Would you say modern foodstuffs are natural or unatural?

Answer 8

It is perhaps overly simplistic to take the line that only natural foods should be commended and that GM plants are unnatural. Arguably, very few of our modern foodstuffs can be termed natural, as they are not derived from naturally evolved crops. Tremendous changes in genetic make-up have been achieved by conventional (i.e. non-GM) breeding methods. As you learnt in Week 1 of this topic, traditional plant breeding involves selection of individuals seen as superior, and then crossing; that is, transferring the pollen of one superior plant to the female parts of another superior plant of the same species. Whilst those suspicious of GM crops do not argue against this form of production of new crops, it is hard to argue that it is in any way natural.

Question 9

What is intraspecific or withing species breeding?

Answer 9

So far in this topic, plant breeding has been discussed in terms of intraspecific or within-species breeding; that is, crossing plants of two varieties from the same species.

Question 10

How could you argue that intraspecific or within species breeding is natural?

Answer 10

It is possible to argue that this type of cross-breeding could at least have some chance of happening naturally in the environment by normal pollination methods. More recent plant breeding methods include interspecific and intergeneric crosses.

Question 11

An organism is classified as living if it is capable of breeding with one another describe how the latin name helps to identify this.

Answer 11

Recall that living things are classified into groups based on the observable characteristics they share with other organisms. A species is defined as a group of organisms capable of breeding together to produce fertile offspring and is denoted with a Latin name consisting of two parts. The first name is the genus that the organism belongs to and the second name denotes the exact species within that genus.

Question 12

The scientific name for the maize (corn) plant is Zea mays. What genus does this species belong to?

Answer 12

The genus is Zea. Species that belong to the same genus have lots of similarities but they are not sufficiently alike to successfully breed together under natural conditions. If you need further refreshment on scientific classification and the binomial naming system, then go to the relevant section of the Primer.

Within the genus Zea there are in fact five species of which Zea mays is just one.

Question 13

Suggest what the term interspecific breeding means.

Answer 13

Cross-breeding plants from different species, so in the Zea spp. example, this would mean artificially crossing plants from two of the five different species together to produce hybrids.

Question 14

What is intergeneric breeding? give an example?

Answer 14

Intergeneric breeding crosses plants from different genera (plural of genus). These plants are even more dissimilar from each other than plants from different species but can be artificially bred together to produce a range of so-called man-made crops. One example is Triticale (Figure 2.1), which is a hybrid between wheat from the genus Triticum and rye from the genus Secale. Triticale is used in animal feeds and (without any level of public concern) in the manufacture of multigrain bread for human consumption.

Question 15

What is haploid breeding?

Answer 15

Haploid breeding (also known as doubled-haploid breeding) involves the treatment of normal (diploid) plants so as to produce haploid offspring, which have only one chromosome from each pair in the nuclei of their cells.

Question 16

What are chromosomes and what is their role within cells?

Answer 16

The chromosomes consist largely of molecules of DNA. These store the cell’s genetic information, which instructs the cell how to make specific proteins. Chromosomes are found in the nucleus of every cell and their number is characteristic of a given species. Ordinary plant and animal cells contain the diploid number of chromosomes, where the chromosomes are found in pairs. Gametes (sperm/pollen and ova) contain a single set of unpaired chromosomes and this is the haploid number. If you need to revisit these concepts, go to the relevant section of the Primer.

Question 17

How are haploid crops produced?

Answer 17

The haploid plants are treated with a chemical that induces each single chromosome to double, producing an identical copy. This means that the plant is homozygous for all traits. The method produces true-breeding crops more quickly than traditional plant breeding, and commercial varieties of around 300 plant species, including barley (Figure 2.2) and maize, have been produced in this way.

Question 18

What is mutation breeding?

Answer 18

Mutation breeding is a technique that involves exposing crop plants to appropriate doses of ionising radiation, or another mutagenic agent. This increases the rate of mutation, and may knock out one or more genes.

Almost all of the resulting mutations are deleterious, and lead to unhealthy and/or infertile plants. Occasionally, a previously unknown feature, such as disease resistance or high yield, arises that may be beneficial, and this can be exploited and a new strain developed.

Question 19

How common are mutated crops (through mutated breeding)?

Answer 19

Mutant varieties of crops are used throughout the world. In China, three mutant rice varieties cover more than 30 million hectares of agricultural land. And in the USA, the mutation-bred ruby red grapefruit, selected to be sweeter and darker in colour, is a massive commercial success.

It has been estimated that more than 32 000 improved crop varieties in more than 200 different species (e.g. see Figure 2.4), have been developed through mutation breeding in the past 50 years, with no evidence of public concern and with very little regulation. Indeed, the current regulatory environment controlling the introduction of new GM crops is driving many biotechnology firms back to this old staple from the biotechnological toolbox`

Question 20

What is marker assisted selection and how is this a step up from traditional methods?

Answer 20

Marker-assisted selection (MAS) is a relatively new technique that uses sophisticated genetic and biotechnological techniques to detect new varieties of plants with useful traits. It relies on an indirect selection technique, which follows the inheritance of a selected marker associated with the desired trait.

Using traditional techniques, finding varieties of a crop plant possessing the characteristics the plant breeder is interested in was a slow and expensive process. For example, looking for rust resistance in wheat would involve growing hundreds of plants, infecting them with rust, then selecting those plants most resistant to the disease and using them for further breeding.

With MAS the idea is that a specific, measurable marker is associated with the inheritance of the trait the plant breeder is interested in; in this case, rust resistance. Frequently, DNA-based markers are selected. These are easily identifiable genes that are located in close proximity, on the same chromosome as the gene or genes thought to govern rust resistance. Being located close to the genes of interest for rust resistance means there is a very good chance they will be inherited together from parent to offspring. Recall from previous studies that the closer two co-located genes are on a chromosome, the greater the chance of them being inherited together. See the relevant section of the Primer for a refresher on this. Hundreds of seedlings of different wheat varieties can therefore be cheaply and quickly screened for the presence of the marker in the laboratory; there is no need to grow the plants to maturity and check for rust resistance in the adult plant, since the presence of the marker indicates that the seedling is likely to be rust-resistant. If the marker cannot be found in a seedling, then the plant is discarded.

Question 21

How can marker assisted selected crops be beneficial to the environment?

Answer 21

MAS is already reaping significant rewards. The first drought-tolerant rice variety, MAS 946-1, nicknamed aerobic rice, developed via MAS was released to the market in 2007. It was a product of cross-breeding between a deep-rooted variety of Japonica rice from the Philippines and a high-yielding Indica variety. The plant requires 60% less water than former varieties. Unlike many rice varieties, it doesn’t need to be planted in paddies, with its roots submerged in water. So it is perfect for growing in drought-afflicted countries or where groundwater supplies are overexploited. The development team at the University of Agricultural Science, Bangalore (Figure 2.5) claim that aerobic rice uses 3000 litres of water less than other varieties for every kilogram of rice produced.

Question 22

Why is the breeding of these types of drought-resistant crop plants so crucial?

Answer 22

With the onset of climate change, new varieties of crop will be required to withstand more extreme environmental conditions. As you will see in Topic 2, water will become an increasingly scarce resource in parts of the world where food is grown today.

Question 23

What is distinctive about GM as opposed to these more orthodox methods of plant breeding?

Answer 23

It can bring about the selective and specific transfer of one or more genes from one species to a radically different organism.

Question 24

What is the downside to more convetional plant breeding?

Answer 24

With more conventional plant breeding, crossing generally requires the combination of two entire genomes. This means that in addition to what may be the single gene of interest, others are brought along in the process, as many as 30 000 from each parent. Take a conventional wheat-breeding programme, where the intention is to introduce a foreign gene from a distantly related cultivar into an existing commercial cultivar. By conventional crossing, not only would the new useful gene be introduced, but also a whole range of other genes. The overwhelming majority of these new genes are unlikely to be advantageous to the cultivar. Some could bring unintended disadvantages. Recall from Week 1 of this topic how time-consuming repeated backcrossing is to dilute in the offspring the effect of deleterious genes from the distantly related cultivar.

Question 25

What is meant by the term ‘reductionist mode of thought’?

Answer 25

A reductionist mode of thought is one that argues that complex phenomena can be explained by analysing the system at a more basic or simple level.

Question 26

What do critic of GM argue in terms of changing genes?

Answer 26

Critics of GM claim that the process involves genetic transformation of a type and degree that is unprecedented. They emphasise factors such as the extensive breaking and joining of the DNA of the host genome and what some call illegitimate recombination and scrambling of both foreign and host DNA at the points where transgenes become inserted. By this logic, GM technologies are imprecise and inefficient. It is claimed that removing genes from their normal context and randomly inserting them in a totally new genetic environment could lead to position effects, resulting in variable levels of transgene expression as well as disruption of host gene function. Critics of GM claim that many of the enthusiastic proponents of GM are following the traditions of genetic determinism and adopting simplistic reductionist modes of thought about the science of genetics

Question 27

What two committees have to assess GM crops to be field tested?

Answer 27

In the UK, for a GM crop to be even field-tested requires assessment by two committees: the Advisory Committee on Releases to the Environment and the Advisory Committee on Novel Foods and Processes. Before commercial cultivation, the trial results are examined by the European Food Safety Authority, and member states in the European Union have the opportunity to veto any crop on any grounds

Question 28

What is the only GM crop to be approved in Europe?

Answer 28

Only one GM crop has been approved for use in Europe since 1998. (This crop is Bt insect-resistant maize; 90% of all the Bt insect-resistant maize grown in Europe is grown in Spain.)

Question 29

Even though the growing of GM is banned in UK and europe. HOw do they get in to our food system?

Answer 29

It may come as a surprise to note, however, that GM animal food (soya bean in particular) is freely imported from parts of the world where GM crops are approved, and fed to European livestock.

Question 30

What may the political considerations of GMO food in europe be?

Answer 30

Public opinion in Europe in 2015 is firmly anti-GM, so political parties proposing relaxing GM-related regulation risk losing their popular support.

Question 31

Why do anti GM campaigners approve of marker assisted selection?

Answer 31

How do anti-GM campaigners feel about non-GM biotechnology? Greenpeace and GeneWatch UK are currently vigorously endorsing marker-assisted selection (MAS) as a superior alternative to genetic modification. They believe that because MAS can be used in a way that respects species barriers (meaning that no genes are transferred between species), it is both ethically sound and as safe as conventional plant breeding. Many scientists working in this area feel that MAS and GM are on the same technological continuum; they rely on the same techniques in genetics and molecular biology and find it bizarre that the regulatory framework treats the products of these two types of related breeding programmes in a completely different way.

Question 32

What is likely the most deleterious effects of GMO's?

Answer 32

It is likely that most deleterious effects of genetic modification, like those of conventional breeding, result in unhealthy or infertile plants, which are not developed further. Commending natural sexual reproduction methods above others might be seen as being more problematic. Natural processes are often error-strewn and may give rise to unexpected outcomes.

Question 33

Why do some GM critics believe it is wrong to interfere with nature at all?

Answer 33

For some GM critics, however, the premise that other methods of selective plant breeding are not truly natural either does not hold much sway. Many believe that it is intrinsically wrong to treat the natural world in an industrial fashion, focusing on our needs and wants, even if the outcome is broadly beneficial. Such anti-GM campaigners view the environment as an object of ethical concern and feel that any interference is morally wrong. This resonates firmly with the idea of sustainability and sustainable agricultural practices, with the overriding aim to ensure that the environment is undamaged for future generations of both people and other species.

Question 34

The 1999 report of The Nuffield Council on Bioethics, Genetically modified crops: the ethical and social issues, suggests that what guidelines should be followed reagrding ethical priciples when considering the evaluation of any new technology and its benefits and risks?

Answer 34

This report suggests that it is important to be guided by the following ethical principles when considering the evaluation of any new technology and its benefits and risks: The principle of general welfare: governments and policy-making institutions should act in the best interests of the citizens. The principle that people’s rights should be maintained – for example, the right of consumers to have freedom of choice as consumers. The principle of justice: both the burdens and the benefits of particular policies and practices should be shared fairly between those affected.

Question 35

If you were to apply these principles to the GM debate, this would quickly raise the question: would the new technology increase food security for the global population? What other specific questions would you need to ask to help determine if the three principles were adhered to by the implementation of GM technology?

Answer 35

The Nuffield Council on Bioethics in their report (1999) selected the following broad questions around GM technology. You may have included some of these or thought of others: Will the technology promote general human welfare, for example by improving food safety or reducing the use of chemical pesticides in agriculture? Does the technology pose unknown risks for consumers and the environment that will impact on general welfare? What implications does the technology have for the rights of consumers, for example the right to be informed about the food one is eating? What implications does it have for the rights of scientists to be free to conduct their research in ways that protect their intellectual integrity? Who will be the principal beneficiaries from the introduction of the new technologies and what obligations do they have to compensate the losers? Trying to use guiding principles of this type does not make assessment straightforward. Such principles can’t be applied rigidly in an abstract way as they reflect absolutes such as what is right or wrong. Their operation depends on the context under consideration.

Question 36

What is precautionary principle?

Answer 36

Current regulation concerning GM crops in the EU is framed to make sure that no harm is done. This is the so-called precautionary principle, which puts the avoidance of harm, to any degree, to the consumer or the environment ahead of any benefits of the implementation of a new technology.

Question 37

What are the implications of a rigorous implementation of the precautionary principle for the deployment of new technology in agriculture?

Answer 37

Although the precautionary principle provides maximum reassurance of safety, it is unlikely that any fully reliable data set could ever fully quantify the level of risk to human health or to the environment in all possible circumstances. Absolute proof of no risk is not possible. Most technologies have associated elements of uncertainty and if the principle is rigidly adhered to there is the risk that significant benefits are forgone and opportunities to make improvements to food security and safety are lost.

Question 38

What would be a sensible approach to making an ethical assessment using the principle general welfare with the use of GM crops?

Answer 38

One sensible approach in making an ethical assessment using the principle of general welfare is to try to weigh up the benefits of a technology against its potential to do harm. Deciding whether GM technology is acceptable, in ethical terms, then involves a judgement about the plausibility and moral weight of competing sets of claims. Individuals may make widely different judgements based on the same information, exposing different underlying values and different views on how scientific information ought to be applied. Nevertheless, any judgement should begin with an assessment of the possible benefits and risks.

Question 39

From your viewpoint, in the response box, list two or three potential benefits of GM crop technology and two or three potential risks.

Answer 39

In terms of benefits, you may have suggested that GM techniques could: raise agricultural productivity increase food provision to poorer developing nations lead to the production of safer, more nutritious foods. In terms of potential risks, you may have suggested that GM crop technology may: harm human health damage the environment, including other organisms favour the interests of large multinational companies, at the expense of smaller providers.

Question 40

Considering the second ethical principle that consumers should have freedom of choice what is mandatory when it comes to GM food in the EU?

Answer 40

Considering the second ethical principle – that of the rights of the consumer to have freedom of choice – for many consumers, this is the right to avoid GM food. Labelling of GM food is mandatory in the EU and in quite a few other countries (Figure 3.1). In the USA and Canada this is not the case, despite the demands of popular opinion (Figure 3.2). However, there is a balance to strike here between the choices the consumer demands and the limits that this places on the supplier to comply. This takes the debate into the realms of the third ethical principle – that of justice.

Question 41

What if labelling was inexpensive, the manufacturer rich, and there was strong public demand for it and yet the likelihood of harm was no greater. Would the argument for labelling be more compelling?

Answer 41

Surely many would argue that a just outcome in this case would be one requiring labelling.

Question 42

Why would policy makers agree to not put GMO on labeling?

Answer 42

Justice might be considered to involve directing the benefits of a new technology to those who need it most. At the same time, the role of policy-makers is, arguably, to strike a fair balance between the competing rights and welfare of individuals, groups, industry and the state. But achieving justice in this way is again not straightforward. The compulsory labelling of the products of GM crops provides choice to the consumer. But suppose that labelling was very expensive to a relatively poor farmer marketing GM crops, and that the likelihood of harm was generally agreed to be minimal. Many people might take the line that any gains from labelling would be outweighed by the damage to the farmer’s livelihood. Achieving justice in this case might involve taking the side of the farmer.

Question 43

How does impracticality affect ethical principles? and what are the limits that is allowed of contamination with organic products in the UK and EU?

Answer 43

It is also true that firm ethical principles are of limited value if they are impractical. For example, the segregation of non-GM and GM food is beset with practical problems, and very modest levels of GM contamination are allowed even in food labelled as organic. Organic food is produced under a strict code of practice, which forbids use of most pesticides, herbicides and artificial fertilisers and above all the use of GM crops. European law allows up to 0.9% contamination, while the Soil Association, the body that ratifies organic food in the UK, allows up to 0.1%.

Question 44

Generally, dissemination of GM technology in low-income countries by not-for-profit research centres and foundations is seen as a good thing. Can you suggest which of the ethical principles this adheres to and why?

Answer 44

The third principle, the principle of justice which suggests that the benefits of the practices are shared by those affected. By removing the effect of large multinational corporations and their requirement to make profits for shareholders, the benefits of the adoption of new technology are more equally shared and the risks of exploitation reduced.

Question 45

In 2014 how much calories per head did the world produce?

Answer 45

Most people are aware that more equal distribution of existing supplies could resolve food shortages. In 2014 the world produced enough food to supply an average of 2800 kilocalories per head of the global population, exceeding the average daily requirement of 2100 kilocalories. Clearly, the problem is not one of insufficient food but of unequal access to food. Should this point be used to argue against supporting technological progress in food farming in developing nations?

Question 46

The agricultural yields of which countries/continents are likely to be most seriously affected by climate change and which the least? How does this compare with the areas of rapid population growth?

Answer 46

Most of the Southern Hemisphere will be adversely affected to some extent: sub-Saharan Africa, India, Pakistan and Bangladesh, most of the Middle East, most of Australia, and most of South and Central America. Unfortunately, with the exception of Australia, these are the same areas of the world where the population is likely to rise the most.

Question 47

Why might climate change actually allow agricultural productivity in some areas to rise?

Answer 47

Many areas of the Northern Hemisphere may see yields rise possibly as a result of additional growth due to enhanced photosynthesis (the process by which plants make food to fuel their growth). Anthropogenic climate change arises from the addition of carbon dioxide to the atmosphere from burning fossil fuels. You will learn much more about this in Topic 3; but it is sufficient to say here that because photosynthesis requires carbon dioxide, the increasing concentration in the atmosphere may allow photosynthesis to proceed more efficiently in countries where water is available and temperatures have not risen too sharply.

Question 48

If the line was taken that GM crops should not become part of agricultural practice in low-income countries, what would be the alternative strategies?

Answer 48

It may well be possible to expand the amount of agricultural land, improve irrigation, increase fertiliser and pesticide input, and make sustained use of conventional plant breeding procedures including newer technologies such as marker-assisted selection. However, there are problems with each of these options: The expansion of agricultural land area has slowed over recent years, reflecting the decreased returns from the land that is available. It is estimated that if world crop yields had not increased threefold between 1960 and 1992 via the Green Revolution, 260–310 million hectares of additional land would need to have been cultivated. To avoid such extra land use over the next 20 years (and the inevitable loss of biodiversity which would accompany this), it would be necessary to triple the yields from the world’s existing farmland. Political factors mean that many countries do not possess the appropriate infrastructure to expand agriculture in the way described. Increased irrigation has to continue as a priority, but this may face sharply diminishing returns, increasing marginal costs and hazards related to access to water. The vexed question of fair access to water will be discussed at length in Topic 2. Increased use of fertilisers and pesticides carries obvious disadvantages, not just because of environmental and health effects, but because of their expense and the problems of lax regulatory control. MAS is extremely useful to bring out the full genetic potential of a given plant, allowing scientists to assemble an array of desirable characteristics within the plant; but if genes for the specific trait sought don’t exist within that species, then it is not an appropriate way forward (Folger, 2013).

Question 49

In your view, who has so far benefited from GM-based agriculture?

Answer 49

In reality, benefits have not accrued to those who have the greatest need. This has been the case within both high- and low-income countries. Instead the benefits of GM farming have accrued largely to the agrochemical multinationals, large-scale farmers and food producers. Few benefits to consumers have been apparent. From an ethical viewpoint, it is clearly unjust that the commercial development for GM has been largely devoted to the large-scale industrialised agriculture prevalent in high-income countries, rather than to the small-scale peasant farmers in low-income countries.

Question 50

Would it be ethically justified to develop GM crops for developing countries, if these were to raise the yield and profitability at the expense of traditional farming methods?

Answer 50

Many people take the line that abandoning traditional agricultural practice would be unethical, partly because of the social disruption such a switch would cause. But what if the degree of gain for the producers and consumers in the developing world was significant? Any solution to this ethical dilemma might be influenced by the fact that many traditional farming practices are not keeping pace with issues such as climate change, with the result that small-scale traditional peasant farming is thought to be increasingly unsustainable in many parts of the world. Of course, if GM crops were found to be harmful to human health or to the environment in some way, the issue of fairness would be judged differently.

Question 51

If a genetically modified crop was able to eradicate a very serious deficiency disease amongst poor children, would it be ethically justifiable to prevent its release and use?

Answer 51

In essence, the issue here is whether the benefits to the child outweigh all other concerns. Assuming the claims made for the crop plant are justifiable – that it does eradicate the disease – then the competing claims of anti-GM campaigners would need to be weighed against the ongoing risk to children’s health.

Question 52

How are second generation crops supposed to be more beneficial?

Answer 52

This last question allows the attention to be turned to the more recent types of GM crops, the so-called second generation. These are crop plants that are genetically modified to be more nutritionally beneficial: to directly benefit the poor amongst the populations of low-income economies. The cost–benefit analysis for these GM foods leads us into a whole new range of new ethical dilemmas.

Question 53

what does vitamin A do and how important for the body is it?

Answer 53

Vitamin A, more commonly known as retinol, is an important chemical intermediate in a number of biochemical processes in mammals. It is involved in vision, and is found in the rod cells of the retina of the eye. These cells are particularly important for effective vision at low light levels, and night blindness is a symptom of vitamin A deficiency (VAD). Vitamin A is also involved in the proper functioning of the immune system. Children who are vitamin A-deficient are prone to serious infections, and often die from relatively minor illnesses, such as diarrhoea or measles. The WHO in 2015 estimated that 250 million children worldwide were vitamin A-deficient, of whom between 250 000 and 500 000 become blind each year. Of these, half died within 12 months of losing their sigh

Question 54

can all organisms produce vitamin A?

Answer 54

Many plants and bacteria can produce vitamin A from simpler molecules, but mammals cannot. Humans must either ingest vitamin A directly, or produce it by breaking down one of a group of dietary molecules called carotenoids.

Question 55

What is one of the most common forms of vitamin A?

Answer 55

Carotenoid molecules contain 40 carbon atoms, and mammals can chemically cleave a number of them to produce either one or two molecules of the 20-carbon retinol. A number of related carotenoid molecules are found in the human diet. The ones that can be converted into vitamin A are referred to as the provitamin A carotenoids. The commonest of these is β-carotene

Question 56

What are antioxidents?

Answer 56

antioxidants, which are chemicals that inhibit damaging oxidation reactions inside cells.

Question 57

Which foods arevitamin A found in?

Answer 57

Vitamin A itself occurs in animal products, particularly in meat, liver, eggs and milk. Carotenoid compounds are found in a variety of vegetables and fruit. You have seen that β-carotene is found in familiar orange carrots (Figure 4.3 and Table 4.2). Lycopene is found in relatively high concentrations in tomatoes.

Question 58

What sort of diet will minimise vitamin A deficiency (VAD)?

Answer 58

Given the wide variety of foods that contain α- and β-carotene, or provitamin A carotenoids or β-cryptoxanthin, any reasonably varied diet that contains sufficient fat will provide adequate sources of vitamin A.

Question 59

In which countries is vitamin A deficiency prevalent in?

Answer 59

VAD is a disease of poverty, found where people are unable to either grow or afford an appropriate diet. It is prevalent in countries where rice is a staple, particularly in South Asia. The rice plant itself contains carotenes: they are found in both the leaves and the husks. Rice that has not been milled (i.e. brown rice) can therefore be an important source of both dietary fibre and carotenes.

Question 60

Just how much of a staple food is rice in the world?

Answer 60

Just how much of a staple food is rice in the world? Well, Asia produces and consumes about 90% of the world’s rice. But rice is also a staple food in Latin America and the Caribbean, and a leading source of protein for the poorest 20% of the tropical population, supplying more protein per person than beans, beef, or milk.

Question 61

What type of molecule is b carotene?

Answer 61

β-carotene is not a protein. It is a hydrocarbon, i.e. a compound containing only hydrogen and carbon atoms

Question 62

Is β-carotene coded for by a gene?

Answer 62

Not directly; genes generally encode proteins. However, β-carotene is produced by a series of biochemical reactions, each of which is catalysed by a specific enzyme. Each of these enzymes is encoded by a specific gene.

Question 63

Explain the metabolic pathway in to the production of β-carotene in plants ?

Answer 63

intermediate compounds and enzymes in the carotenoid metabolic pathway. IPP is first converted to GGPP (using the enzyme GGPP synthase), phytoene synthase then converts GGPP this to phytoene, phytoene desaturase converts phytoene to zeta carotene, and zeta carotene desaturase converts zeta carotene to lycopene. Here the pathway splits, with lycopene being converted to either alpha carotene or beta carotene, catalysed by a lycopene cyclase enzyme. Finally, alpha carotene is converted to lutein and beta carotene to zeaxanthin.

Question 64

Given that GGPP is already present in the cells of the rice endosperm, how many genes have to be introduced to allow its conversion into β-carotene?

Answer 64

The process involves four stages, each catalysed by its own enzyme. In order to produce these four enzymes, at least four genes would have to be introduced.

Question 65

Potrykus’ team planned to introduce each gene separately into separate sets of rice plants, and then perform conventional crossing experiments between these four sets of transformed rice in an attempt to produce a plant with all four enzymes active in the endosperm. What are the two methods you have learnt about that are available for the genetic transformation of plants?

Answer 65

Agrobacterium-mediated transformation and microprojectile bombardment (gene gun)

Question 66

You predicted that Experiment 1 might produce red rice. What has happened?

Answer 66

The rice unexpectedly showed a yellow colouration, strongly suggesting that any (red) lycopene produced had been converted to yellow β-carotene. It appears that the rice grains are able to produce their own lycopene β-cyclase. It may be that at high concentrations of lycopene, the production of this enzyme is induced, or it may be that the enzyme is already present.

Question 67

The road to better nutrition is not paved with gold and, hence, agribusiness has not centred its efforts on the nutritional value of food. The work that culminated in the production of golden rice was funded by grants from the Rockefeller Foundation, the Swiss Federal Institute of Technology and the European Community Biotech Program. Like the plant varieties that made the Green Revolution so successful, the rice engineered to produce provitamin A will be freely available to the farmers who need it most. One can only hope that this application of plant genetic engineering to ameliorate human misery without regard to short-term profit will restore this technology to political acceptability. What three key points does this express?

Answer 67

Previous work on genetic modification has been shaped by the need of Western agrochemical multinationals to make a profit. Public and charitable funding means this work may be made freely available to the most needy. This breakthrough may help to persuade more people that GM crops are acceptable

Question 68

What are the 3 main issues raised by critics of golden rice GR1?

Answer 68

Three of the main issues raised by critics of golden rice are: its poor vitamin A content, concerns over the effects of new selection methods, it's not the preferred type of rice in much of south-east Asia.

Question 69

An additional aim of more recent work on golden rice was to remove the antibiotic resistance markers, reflecting the concern that the resistance might be transferred to wild bacteria and reduce the effectiveness of antibiotics when treating human and animal disease. Why is a selective marker needed?

Answer 69

A selective marker gene is required in the early stages of developing genetically modified (GM) plants. In the process of inserting new genes into plant cells, called transformation, not all the plant cells are transformed. To identify cells that have been successfully transformed, a marker gene is used.

Question 70

What are the concerns of opponents of GMO rice?

Answer 70

The concerns of opponents of golden rice include: Other vegetables such as carrots could be used instead of golden rice – technology is not needed. GMOs will put multinational companies in control of agriculture instead of farmers. Cost of seed has risen and farmers’ income has declined. The concerns expressed by opponents of golden rice here include: It is not natural. Risks are unknown and there will be negative impacts on environment and human health. Pushes GM technology and promotes the interests of multinational companies. Humans are being experimented on.

Question 71

The breeding (by any means) of crops to increase their nutritional value is known as biofortification. Why is the matoke variety of banana a good candidate for biofortification?

Answer 71

The matoke banana is a staple food, with Ugandans consuming very significant amounts each day. Fortifying the crop with β-carotene could therefore have a significant effect on the vitamin A status of the population.

Question 72

What challenges does this research project face and are there any differences in relation to other similar projects?

Answer 72

Public acceptance of the yellow-coloured fruits is an issue, as is public opposition to GM and the perceived risks it represents. Unlike many other similar projects, this is a local initiative.

Question 73

Why are some people more confident in producing golden bananas over golden rice?

Answer 73

They have developed the new variety in conjunction with Uganda scientists and farmers. They are working with a crop plant variety that is eaten by the local population. The project is charitably funded and there is no multinational company involved . The project makes use of a sterile crop (banana is sterile), so there is little risk that transgenes can be transferred to other plants. Encourage local planting using multipliers, to ensure there is enough crop available. Involve non-governmental organisations (NGOs) to support farming and markets. Inform consumers about the crop – overcoming fears that it is GM, encouraging the health benefits. Demonstrate that the crop is palatable. Work with traders, markets and communities to introduce OSP. Ensure that the crop is generating income.

Question 74

What problems arise from the solution to increase the diversity of foods available?

Answer 74

One solution is to increase the diversity of foods available by encouraging people to grow their own. Some countries and agencies have adopted practices that encourage the family to grow fruits and vegetables in home plots and in urban allotments. This can certainly help improve the variety of foodstuffs in the diet, but poverty is an issue here too. Often the poorest of the poor must allocate all their resources to the provision of staple foods such as rice to supply their energy needs. For these households, diverting resources towards fruit and vegetables is unlikely to be successful until families have satisfied their daily energy requirements (Ruel et al. 2005). Evidence shows that fruit and vegetable consumption across the world is correlated with rising incomes.

Question 75

What is fortification?

Answer 75

the supplementation of a nutrient in to other foods

Question 76

Looking back at the information in this section overall, what are the four strategies by which people can ensure they obtain essential micronutrients such as vitamin A, and which of these methods would you think are the most cost-effective and why?

Answer 76

Dietary diversity Food fortification (adding specific nutrients to foods after production) Supplementation (using pharmaceutical preparations of specific nutrients administered as medicines) Biofortification (modification of the parent crop to produce an enriched foodstuff, either by GM techniques or conventional plant breeding)

Question 77

Many would argue that a one-time investment in a biofortified crop, whether it is produced by genetic modification or conventional breeding, is the most cost-effective method to tackle this type of deficiency. Why can’t rice be biofortified to contain provitamin A carotenoids by natural plant breeding methods?

Answer 77

There are no varieties of rice in the world that store provitamin A carotenoids in the endosperm of the grain and so selective breeding is not possible.

Question 78

Why does Vandana Shiva feel that golden rice is not needed?

Answer 78

Vandana Shiva feels that golden rice is not needed and she claims that the golden rice project is merely a Trojan horse; an attempt to give genetic modification a humanitarian face. She is firmly of the opinion that GM technology is a ‘techno-fix’ solution, which will only profit the global multinational agribusinesses and not alleviate VAD

Question 79

In this regard, the terms ‘risk’ and ‘hazard’ are particularly important. ENTRANSFOOD (European Network on Safety Assessment of Genetically Modified Food Crops) has defined the terms as?

Answer 79

Risk is defined as the likelihood that, under particular conditions of exposure, an intrinsic hazard will represent a threat to human health. Risk is thus a function of hazard and exposure. Hazard is defined as the intrinsic potential of a material to cause adverse health effects; implicit in the definition is the concept of severity and adversity of the effect.

Question 80

In the early 1990s, biotechnology companies were preparing to market the first food products derived from GM crops. This provided a challenge to legislators. There were no precedents to guide them as to how to approve or ban novel food products. The methods used to approve pharmaceuticals, summarised above, did not seem to transfer easily to whole food products. Why might this have been the case?

Answer 80

Determining the NOAEL and hence the ADI of a whole food could prove exceptionally difficult; force-feeding laboratory animals large quantities of a single foodstuff would be impractical and ethically unacceptable.

Question 81

What is NOAEL?

Answer 81

No Observable Adverse Effect Level (NOAEL)

Question 82

the Organisation for Economic Cooperation and Development (OECD, a group representing high-income countries, which seeks to provide uniform guidelines for its member countries) gathered a group of 60 regulatory scientists nominated by its member governments. In 1993, after two years of deliberation, they published a report, which concluded what?

Answer 82

For foods and food components from organisms developed by the application of modern biotechnology, the most practical approach to the determination of safety is to consider whether they are substantially equivalent to analogous conventional food product(s), if such exist. If a new food or food component is found to be substantially equivalent to an existing food or food component, it can be treated in the same manner with respect to safety. No additional safety concerns would be expected. Where substantial equivalence is more difficult to establish because the food or food component is either less well-known or totally new, then the identified differences, or the new characteristics, should be the focus of further safety considerations. (OECD, 1993)

Question 83

This was the point at which the so-called ‘principle of substantial equivalence’ became firmly established as a point of international trade law. The report identifies two distinct classes of food or food components derived from genetically modified organisms. What are they?

Answer 83

Hide answer The report made a distinction between GM foods that could be considered substantially equivalent and therefore safe, and those where they identified differences or new characteristics. The latter should be the focus of further safety assessment.

Question 84

Why would some scientists argue that substantial equivalence is pseudoscientific?

Answer 84

Substantial equivalence is a pseudoscientific concept because it is a commercial and political judgement masquerading as if it were scientific. … It should be replaced with a practical approach that would actively investigate the safety and toxicity of GM foods rather than merely taking them for granted, and which could give due consideration to public-health principles as well as to industrial interests.

Question 85

Can you recall any of the specific food safety-related scares of the 1990–2000 period and any more recent food issues in Europe?

Answer 85

Bovine spongiform encephalopathy (BSE), a newly emerged disease of cattle, posed a serious threat to human health in the 1990s. There have also been food scares related to Salmonella spp. (in eggs in the UK in 1988) and E. coli spp. contamination of foodstuffs (most recently in organic beansprouts grown in Germany, 2011), and the fraudulent use of horsemeat in meat products (2013).

Question 86

Why is public awareness and opposition different in the USA and EUrope?

Answer 86

In contrast in the USA, significant public awareness and opposition to GM food did not emerge until around 1999 and this was largely a response to developments in Europe. Why did this difference in public opinion exist? In Europe the introduction and regulation of GM food through the 1990s played out against a backdrop of other serious food-related scares and significant failures of food regulation by governments and European regulatory bodies. These very well-publicised food scares led to a significant loss of public confidence in governments to regulate food safety and a mistrust of multinational companies to put the safety of consumers above potential profits.

Question 87

A modern approach to the hazard assessment involved in producing a new GM variety and/or food product. Note that these guidelines are applied on a case-by-case basis, so every potential new crop or product goes through the whole safety assessment protocol. This level of analysis addresses all of the known issues of concern for human health and seeks to verify if all the following questions have been satisfactorily answered. All new genetic material has been examined in detail. What questions could be asked in regards to new genetic detail?

Answer 87

Where did the new genetic material come from? What is its function? How was it put into the GM food? How is it arranged within the genetic material of the plant or animal?

Question 88

A modern approach to the hazard assessment involved in producing a new GM variety and/or food product. Note that these guidelines are applied on a case-by-case basis, so every potential new crop or product goes through the whole safety assessment protocol. This level of analysis addresses all of the known issues of concern for human health and seeks to verify if all the following questions have been satisfactorily answered. The new genetic material is stable and is passed on in a predictable way from generation to generation. What questions could be asked in regards to the stability of genetic material and whether it can be passed on?

Answer 88

Is the new genetic material stably integrated within the DNA of the GM organism? Is the novel trait expressed consistently over a number of generations?

Question 89

A modern approach to the hazard assessment involved in producing a new GM variety and/or food product. Note that these guidelines are applied on a case-by-case basis, so every potential new crop or product goes through the whole safety assessment protocol. This level of analysis addresses all of the known issues of concern for human health and seeks to verify if all the following questions have been satisfactorily answered. All new proteins have been examined in detail. What questions could be asked about proteins being examined in detail?

Answer 89

Where and when are the new proteins found in the plant or animal? Do they have the expected size, structure and biological activity?

Question 90

A modern approach to the hazard assessment involved in producing a new GM variety and/or food product. Note that these guidelines are applied on a case-by-case basis, so every potential new crop or product goes through the whole safety assessment protocol. This level of analysis addresses all of the known issues of concern for human health and seeks to verify if all the following questions have been satisfactorily answered. The new proteins are unlikely to be toxic or allergenic. What questions could be asked about this?

Answer 90

Do the new proteins come from living organisms that contain no major toxins or allergens? Are the new proteins similar to known toxins and allergens? Do the new proteins possess other physical and biochemical characteristics typical of toxins and allergens?

Question 91

A modern approach to the hazard assessment involved in producing a new GM variety and/or food product. Note that these guidelines are applied on a case-by-case basis, so every potential new crop or product goes through the whole safety assessment protocol. This level of analysis addresses all of the known issues of concern for human health and seeks to verify if all the following questions have been satisfactorily answered. The new proteins do not cause any detectable toxicity in animal studies. What questions could be asked about this?

Answer 91

When the purified new proteins are given in large doses to rats or mice, are there any adverse effects?

Question 92

A modern approach to the hazard assessment involved in producing a new GM variety and/or food product. Note that these guidelines are applied on a case-by-case basis, so every potential new crop or product goes through the whole safety assessment protocol. This level of analysis addresses all of the known issues of concern for human health and seeks to verify if all the following questions have been satisfactorily answered. The potential transfer of new genetic material to bacterial cells in the human digestive tract will not have a significant impact on human health. What questions could be asked about this?

Answer 92

Are antibiotic resistance genes present? Is the corresponding antibiotic used in human or veterinary medicine? What would be the health impact if the new genes were to be transferred to bacteria in the human gut?

Question 93

A modern approach to the hazard assessment involved in producing a new GM variety and/or food product. Note that these guidelines are applied on a case-by-case basis, so every potential new crop or product goes through the whole safety assessment protocol. This level of analysis addresses all of the known issues of concern for human health and seeks to verify if all the following questions have been satisfactorily answered. The composition of the food, including naturally occurring toxins, allergens and anti-nutrients (compounds that interfere with the absorption of nutrients), is not significantly altered compared to the non-GM food. What questions could be asked about this?

Answer 93

Is the composition of the food (proteins, fats, fibre, carbohydrates, amino acids, vitamins, minerals, water content, other biologically active molecules) substantially different from that of the conventional food? If so, does the difference found in the GM food affect the safety of the food, and will it make the food less nutritious or healthy?

Question 94

Both reports highlighted areas of scientific uncertainty; for example, relating to the ease with which GM plants were able to invade new habitats. In neither report is there any claim that GM foods are absolutely safe. However, the panel pointed out that there ‘has been no verifiable untoward toxic or nutritionally deleterious effects resulting from the cultivation and consumption of products from GM crops’. How much credibility do you personally attach to such a reassurance about safety and how convincing do you find this argument about the lack of long-term influence on exposed populations from ingesting GM products?

Answer 94

Safety assessments can be problematic as they always include a degree of ambivalence. It is only possible to say that there is no evidence that a product may be harmful, and of course the absence of evidence is not seen as equivalent to the absence of harm. On the subject of GM food, there is a good amount of non-specific evidence from the USA that the long-term effects of eating GM food have not shown obviously serious effects on the population. However, as GM food has not been routinely labelled in the USA these data are not terribly rigorous. Given the absence of human trials it is not possible to say whether deleterious effects from GM are simply being masked by general improvements in health care and environmental standards. Very large-scale epidemiological studies would be required to determine a causal link between food-related illness and GM products.

Question 95

The key objective of the national dialogue on GM was to allow the exchange of views and information – members of the public would presumably learn more about the issues; experts and policy-makers would learn more of the reasoning behind the public’s concerns. Can you think of any problems involved in running such a dialogue

Answer 95

One problem is the difficulty of sampling public opinion in a representative way, trying to ensure that those involved constitute a representative cross-section of the public. Another problem, given the strongly polarised views on the issue, might be how to encourage a meaningful two-way debate, with both sides listening.

Question 96

Briefly summarise the outcomes of GM nation?

Answer 96

Very briefly, here is a summary of the outcomes of GM Nation? Report, Findings of the Public Debate (GM Nation, 2003). The unedited version of the report can be found on The National Archives website. People are generally uneasy about GM. The more people engage in GM issues, the more their attitudes harden and the more intense their concerns become. There is little support for early commercialisation. There is widespread mistrust of Government and multinational companies. There is a broad desire to know more and for further research to be done. Developing countries have special interests.

Question 97

Here is my input as to why I am against the relaxation of regulations of GMO crops to put forward in the submission, which relates to the golden rice story. Whilst the scientific achievements of GMO is admirable, we can learn something from the invention of golden rice and why it is just simply not needed. GMO's have been opposed by the public for decades now and rightly so as not enough a scientific research has gone in to proving their safety. The genetic modification of rice to improve its nutritional quality in vitamin A to target communities that are deficient (golden rice), the idea behind it may seem positive but it is neither sustainable or realistic. The targeted population are those that are poor so the purchase of these GM seeds for most would not even been an option and even if it was, the crops can not reproduce nutrient rich vitamin A offspring leaving vulnerable farmers without control of their seeds and therefore food supply. There are far better Vegetables such as carrots and tomatoes, as well as meat, butter, and milk, can provide the vitamin or its precursors, but many families in poor countries don't have access to them. t argued that the crop was an industry PR ploy—seed company Syngenta was involved in the project, the group pointed out—designed to win over a skeptical public and open the door to other GM crops. Golden rice did not attack the underlying problem of poverty, Greenpeace said; besides, other, better solutions to vitamin A deficiency existed. There are already foods that can be grown naturally that are abundant in vitamin A, such as brown rice with the husks or carrots - GMOS not needed. He says giving out supplements, fortifying existing foods with vitamin A, and teaching people to grow carrots or certain leafy vegetables are, for now, more promising ways to fight the problem. There is enough calories per head but problem with distribution GR1 - did not contain enough B carotene GR2 does Is this propaganda? targeting poor people to improve the popularity of GMO with no real interest of their safety. Poorer people are usually not very well educated so may not fully understand what a GMO and all the issues surrounding them and the facts. although the idea is to help those suffering from illnesses relating to poverty it is just not realistic. The public in in Europe have made it clear that they do not want to consume GMO and should have a right to. not sustainable - cannot regrow the seeds with vitamin A benefits, even if they could they wouldn't be allowed as its not their property. Alternatively you may be deeply concerned that the potential risks are still not fully described or quantified and feel that a clear scientific consensus has still not been reached on the safety of GM. Poor people are most likely deficient in other nutrients that are responsible for the uptake of B carotene. Too much b carotene could pose problems to those who are not deficient - causing other ill effects most would argue that there are better less exhuasting solutions to vitamin A deficiency

Answer 97

Here is my input as to why I am against the relaxation of regulations of GMO crops to put forward in the submission, which relates to the golden rice story. Whilst the scientific achievements of GMO is admirable, we can learn something from the invention of golden rice and why it is just simply not needed. GMO's have been opposed by the public for decades now and rightly so as not enough scientific research has gone in to proving their safety. The genetic modification of rice to improve its nutritional quality in vitamin A to target communities that are deficient (golden rice), the idea behind it may seem positive but it is neither sustainable or realistic. The targeted population are those that are poor so the purchase of these GM seeds for most would not even be an option and even if it was, the crops can not reproduce nutrient rich vitamin A offspring leaving vulnerable farmers without control of their seeds and therefore food supply. There are far better and less exhaustive solutions to tackling vitamin A deficiency in low income countries such as the growth of naturally vitamin A rich vegetables (carrots and tomatoes) or fortification of foods, if access to these are a problem then surely it would be no different accessing 'golden seeds'. There is also the issue that too much vitamin A to those that are not deficient could be dangerous or poor people are most likely deficient in other nutrients that are responsible for the uptake of beta carotene. Members of the public may speculate that this is a tactic to improve the popularity of GMOs by targeting people in poverty with no real interest of their safety to benefit global multinational agro-businesses and make GMOs more acceptable worldwide. Education and awareness could also be a problem if poverty stricken people had no knowledge of GMO's and understanding of all the issues surrounding them. Claims are made that GM crops could improve global food security.

Question 98

How many photosynthetic patheways are found across all species of plants? and what are they?

Answer 98

There are two common photosynthetic pathways found across all species of plants The 4-carbon pathway (C4 pathway) and much less efficient and less productive 3-carbon pathway (C3 pathway).

Question 99

Explain the difference in the C3 and C4 pathway?

Answer 99

It is the pathway of the dark reactions that differs between C3 and C4 plants. In C3 plants, carbon dioxide is absorbed from the atmosphere into the leaves of the plant. Within the chloroplasts of specific leaf cells called mesophyll cells (Figure 7.1), it is then combined with a five-carbon compound called ribulose bisphosphate. The enzyme that catalyses this reaction is called ribulose bisphosphate carboxylase oxygenase or RuBisCO for short. Unfortunately, RuBisCO isn’t a particularly efficient enzyme and most of the inefficiency of photosynthesis can be attributed to this one enzyme. Plants compensate for this inefficiency by having a great deal of RuBisCO; as much as half of all the protein in plants consists of this one enzyme. Fortunately for some plants native to hot, arid countries, such as maize (Zea mays) and sugar cane (Saccharum officinarum), evolution has resulted in a more efficient system of carbon dioxide fixation. These are the C4 plants and they get around the poor showing of RuBisCO by using an additional enzyme to capture carbon dioxide before pumping it, ready concentrated, to RuBisCO. Figure 7.1 and Audio 7.1 describe how this ingenious process works in C4 plants and the differences in the anatomy of the leaves in C3 and C4 plants.

Question 100

What percentage of plants use the C3 pathway?

Answer 100

85%

Question 101

How much more effective is the C4 pathway at fixing carbon dioxide

Answer 101

The action of the pump increases the amount of carbon dioxide in the bundle sheath cells to such a level that RuBisCO combines with carbon dioxide very efficiently, leading to an increase of the photosynthetic rate of up to 50%

Question 102

What 4 major crop plants use the c4 pathway?

Answer 102

Only four major crop plants in the world are C4: maize, sugar cane, sorghum and millet.

Question 103

Only four major crop plants in the world are C4: maize, sugar cane, sorghum and millet. So the question is: can scientists modify useful C3 crops such as rice to be photosynthetically supercharged in the same way? The IRRI/Cambridge scientists are investigating ways in which rice can be modified to do just this, but potentially both biochemical and anatomical changes are needed in the rice plants. What anatomical changes would be needed?

Answer 103

C3 plants lack a whole cell type – the bundle sheath cells – which are required for the operation of the C4 pathway (see Figure 7.1).

Question 104

Interestingly, the team have begun by studying how C4 plants evolved in the first place and how they came to dominate certain types of hot, arid ecosystems. In the very distant past, as atmospheric carbon dioxide levels fell it is likely that C4 plants, with their superior photosynthetic rate in high temperature and low water environments, simply outcompeted their C3 neighbours. If the scientists can establish which genes are responsible for the C4 characteristics, GM C4 rice and other crops are highly possible. In addition to the added yield of C4 rice, what other advantages might it have?

Answer 104

Two advantages are: C4 plants grow in more arid conditions, which may be significant in the light of climate change. C4 plants have much less RuBisCO than C3 plants; this means less nitrogen is required (most enzymes are proteins and proteins contain nitrogen) for plant growth, hence less fertiliser in agricultural settings.

Question 105

Why, if photosynthesis is more efficient in C4 plants, haven’t all plants evolved to use the C4 mechanism?

Answer 105

The C4 pathway requires more energy to fix a molecule of carbon dioxide than the C3 pathway does. The C4 pathway therefore only benefits plants growing in hot, sunny conditions, where the photosynthetic rate is high. Under more temperate conditions, the additional energy use required is not adequately traded off by a significant rise in photosynthetic rate.

Question 106

Why would scientists want to produce C4 wheat and rice?

Answer 106

The plant biochemistry described here is very complex so try not to get too bogged down in the details. In terms of increasing the yields of crop plants, the issue is simple: understand the mechanism by which C4 plants increase their photosynthetic output, isolate the genes responsible and find a way to introduce these genes to adapt photosynthesis in the C3 rice and wheat plants we routinely use for food. The aim is to produce C4 versions of wheat and rice that are around 50% more productive while using less water and fertiliser. Scientists are optimistic this can be done within 20 years.

Question 107

Why can’t marker-assisted selection be used as a method of selectively breeding the C4 pathway into rice plants?

Answer 107

There are no varieties of rice that contain the genes for the C4 pathway, so these genes must be supplied from other plant species.

Question 108

What group of enzyme is responsible for gene editing?

Answer 108

One of these groups of enzymes, known as zinc finger nucleases, can allow the gene to be inserted in a known and controlled part of the recipient’s genome where it will be optimally expressed, so-called genome editing.

Question 109

How can a gene be 'edited'?

Answer 109

A more recent, quicker and cheaper technique called CRISPR is now enabling small laboratories and companies to edit genomes . These types of techniques have now paved the way for a completely new approach to genetic improvement of crops. Instead of inserting a foreign gene, the next step, using this highly specific DNA cutting tool, is to modify the existing gene in the plant to confer the traits of interest (Cressy, 2013). This is referred to as site-directed mutagenesis where single mutations are induced at specific target sites in genes. The end-product is seemingly indistinguishable from its non-GM counterpart, potentially blurring the boundaries between GM and non-GM. These are effectively genetic modifications without the actual transfer of genes; some people feel this might help overcome some of the public hostility to genetic modification. With climate change and the warming of large areas of the world where food crops are grown, crops with higher yields coupled with decreased water requirements will be extremely valuable.

Question 110

What trait are the scientists attempting to modify within the Ranger Russett potato? What gene is targeted in this process?

Answer 110

Potatoes usually accumulate sugar when stored. When fried, these stored potatoes release acrylamide, a known carcinogen. Gene editing will modify this trait to minimise both the sugar content and acrylamide release, thereby allowing potatoes to have a longer storage life with no harmful effects. The gene that produces the enzyme to convert sucrose to glucose and fructose is rendered inactive.

Question 111

What advantage does this biotechnological method have over traditional genetic modification techniques for the companies researching them?

Answer 111

The regulations (and therefore the lengthy approvals/risk assessment approach) regarding genetically modified crops do not apply to these gene-edited plants, as no foreign genes have been transferred.

Question 112

What advantage does this biotechnological method have over traditional genetic modification techniques for the companies researching them?

Answer 112

The regulations (and therefore the lengthy approvals/risk assessment approach) regarding genetically modified crops do not apply to these gene-edited plants, as no foreign genes have been transferred.

Question 113

What is the argument that GM crops cannot be the solution to world hunger?

Answer 113

The argument that there are purely technological, large-scale solutions to world hunger ignores the issue that we probably grow enough food but that it does not reach the people experiencing the lowest food security. Unless issues of poverty, economics and food distribution are tackled, no amount of new technology will actually make a difference. There are many global movements trying to influence agricultural policy throughout the world. One such movement is La Via Campesina, founded in 1993 and comprising local and national organisations all over the world. It represents some 200 million farmers worldwide. La Via Campesina (literally The Peasants’ Way) is completely independent of all economic and political affiliation and seeks to fully realise the concept of food sovereignty. Food sovereignty is the right of peoples to healthy and culturally appropriate food produced through sustainable methods and their right to define their own food and agriculture systems.

Question 114

What is acroecology?

Answer 114

An ecological approach to agriculture that views agricultural areas as ecosystems and is concerned with the ecological impact of agricultural practices.

Question 115

Can you recall an agroecology-type project already mentioned during this week’s study?

Answer 115

The orange sweet potato is one such project where HarvestPlus is working with families and small communities in African countries to improve the vitamin A supply of local people.

Question 116

The next card is a brief summary of intensifiation of agricultaral practices using natural processes

Answer 116

97% of all farms in the world are less than 2 hectares. 70% of farmers in those farms are women. 50% of the food eaten by the world’s population comes from small-holder family farms farming on only 20% of the world’s land. We do produce enough food to feed the world but market demands means food cannot reach the hungry. We aren’t producing the correct amounts of food types we need – we grow 50% more grain than we need but insufficient amounts of milk, seeds, fruits, vegetables and nuts. Red meat – we produce five times more than we need for a healthy balanced diet; meat requires soya beans to feed animals. Obesity is as significant as hunger. Agroecology is the application of ecological concepts and principles to the design and management of sustainable food systems, or farming with nature. Agricultural systems should mimic the natural ecosystems (e.g. rice paddy plus fish plus ducks) and can be on a large and commercial scale. Farmer-to-farmer knowledge sharing – social organisation is vital.