Biotechnology and New Foods

With the emerging of the global village, many societies have been exposed to foods that they are unfamiliar with. For example, tofu an ancient food from the Far East has only just found its way into the western recipe books. Many foods seem new to us but are in fact ancient in the places where they come from.

Scientists are also busy creating new foods in laboratories around the world. Their creations are made in response to the necessity to ensure crop success, increased shelf life and higher nutritional value of the foodstuff. In the time line on page 3, it can be seen that the FLAVR-SAVR tomato was the first whole food that made its way onto the supermarket shelves in the US.

While breeding and selection have provided many new fruits and vegetables and better production and quality, there are some characteristics that cannot be introduced into plants and animals through breeding. These are characteristics that are not already in the genes of the crop or animal, such as tolerance to fungi in strawberries and disease tolerance in certain farm animals. When scientists discovered that genes in animals, plants and microorganisms are made of the same molecules and work in the same way, they started to move genes between organisms to see if this could give new characteristics. It does!

This is called genetic modification and it is being used to help food production around the world. Genetic modification enables scientists to move just the genes they want, rather than moving many genes as happens in breeding. Using this new technology scientists have safety put insect tolerance into maize and cotton, virus tolerance into potatoes and fungal tolerance into strawberries. The new crops have enabled farmers to use fewer chemicals and this will be good for our environment and for us. All of these new crops are tested for safety before they are approved. Future crops will have resistance to drought and be able to grow in poor soil - both of which will make food production much easier in Africa.

(Adapted from: Dining on DNA. An exploration of food biotechnology. Montana State University Extension Service. 1996)

Let us carry out our own genetic modification simulation. We are going to attempt to create a chocolate flavoured cherry by combining a gene coding for chocolate with DNA from a cherry tree.

Requirements:

• Cocoa DNA (linear paper DNA)
• Restriction enzyme (scissors)
• Plasmid DNA (circular paper DNA)
• ligase (tape)

Situation:

The large ArnieJac Sweet Factory has hired laboratory to conduct a very important project. The company is attempting to develop a new product; chocolate-flavoured cherries. Consumer surveys indicate that people love the combination of chocolate and cherries and the ArnieJac Sweet Factory wants to be the first to put these delicious morsels on the market. You are the laboratory technician given the task of altering the DNA of a cherry tree so that it bears a fruit that has a chocolate flavour to it.

The "bigshot" scientist in your laboratory has isolated a gene in the cocoa bean which codes for the delicious chocolate flavour. It is up to you as laboratory technician to remove this gene from the cocoa bean and insert it into the cherry seedling so that the new chocolate flavour cherry results. If you follow the directions below closely, you are bound to get a promotion and probably a big raise too!

Pre-activity questions:

1. Using a dictionary, textbook or your background information, define the following terms:vector, ligase, restriction enzyme, plasmid
2. Read through the protocol and answer the following questions: What on your list of requirements represents
   a the vector? Why?
   b a restriction enzyme? Why?
   c ligase? Why?
3. In your own words, state why scientists may want to use recombinant DNA technology.

Procedure:

1. Before beginning your Nobel Prize-winning procedure, please make-sure you have grasped the background information given above. There is lots of information here which will help you with your pre-activity questions, the actual procedure and the post-activity questions.
2. Complete your pre-activity questions.
3. Removing the desired gene from the linear cocoa DNA.
   • Pick up your restriction enzyme (or scissors).
   • Begin on the top of your cocoa DNA ladder at the end that indicates "start" (the 5' end) read the bases of the strand until you have read an AGCT sequence all in a row in that order.
   • Use your restriction enzyme (scissors) to make the cut after the A in the 4-base sequence.
   • Continue to make cuts after the A in every 4-base AGCT sequence.
   • Now begin reading the DNA on the bottom strand of your cocoa DNA ladder. Start reading from the end that indicates "start" and look for the AGCT sequence all in a row in that order.
   • As before, make a cut after the A in every 4-base AGCT sequence.
   • One cut on the top of the cocoa DNA strand should be 2 bases (rungs) away from the cut on the bottom cocoa DNA strand. Cut through the hydrogen bonds right down the middle of the DNA ladder in order to connect the two closes cuts.
   • Repeat this step on the opposite end of the DNA ladder. You should make a total of two cuts down the middle of the ladder, right through the hydrogen bonds.
   • Remove the strip of DNA that comes out of the DNA ladder. This piece of DNA should have two exposed rungs and a central portion of the ladder intact. It contains the chocolate flavour gene and should be shaped like this:
     

                             +---------------------+
                             | GC                  |
                             +----+                +----+
                                  |                  CG |
                                  +---------------------+
     

   • Put this DNA aside for the moment and move on to the plasmid.
4. Getting the plasmid ready for insertion of the gene:
   • Cut your circular plasmid out so that it looks like a large circular do-nut ring (make sure the middle of the do-nut is cut out).
   • Each of the two strands of the circular plasmid is to be read in a certain direction as indicated by the arrows on the plasmid.
   • Beginning on the outside at the arrow, start reading along the plasmid in the direction of the arrow until you come across an AGCT sequence all in a row.
   • With your restriction enzyme (scissors), make a shallow cut (only to the middle of the ring after the A in every AGCT sequence.
   • Now going in the opposite direction read along the inside loop of the plasmid, reading until you come across the AGCT sequence on the inside DNA strand.
   • With your restriction enzyme, make a shallow cut after the A in every AGCT sequence.
   • Once again, each cut on the inside loop should be two rungs (bases GC) away from a cut on the outside loop.
   • Cut through he hydrogen bonds right down the middle of the plasmid loop in order to connect each of the two closes cuts.
   • With the final cut, open the loop and look closely at the two exposed rungs.
5. Insertion of the new gene into the plasmid (recombination)
   • Look at the strip of DNA that you removed from the cocoa DNA.
   • Compare the strip with the cut-open plasmid DNA.
   • Can you see how they match together? The two pieces of DNA fit together like a puzzle.
   • Match the shapes as well as the bases (A goes with T and C goes with G).
   • Take out your ligase (tape) and insert the cocoa DNA into the plasmid loop.
   • You have just inserted the cocoa gene for chocolate flavour into the plasmid, and now the plasmid can be used to carry the cocoa chocolate flavour gene into cherry plant!

DNA as Video Tape

Let us build an analogy for Genetic Modification that will help us to understand it better.

Introductory fact sheet

DNA is often called the genetic blueprint of an organism. But DNA is more like videotape than a blueprint.

s with all analogies, this one eventually breaks down. Cells are alive and grow and multiply, and organisms evolve - videotapes are static, not-living organisms; the information content stays the same until you edit or copy over it. But the analogy is useful because of all the other similarities between DNA and videotape.

Table of the similarities and differences between DNA and a videotape

Read the article below and answer the following questions:

1. Which genetically modified organisms are currently available in South Africa?
2. What benefits do GMO's have over their naturally occurring counterparts?
3. Organic farmers argue against the use of GMO's. What is their argument and on what do you think it is based?

Having heard all this I started to wonder what genetically improved (GI) foods we are already eating in South Africa. My search took me to the Directorate of Genetic Resources in the National department of Agriculture and there I discovered quite a lot is happening in this country.

Field trials with GI crops have been underway since 1990 and in this time over 150 trials have been carried out on 13 plant types and several microbes. Only two of these have been approved for cultivation in South Africa: insect tolerant cotton and insect tolerant maize. Both have passed thorough human and environmental safety tests and both have the potential to benefit our food production, environment and quality of lives.

In addition, the government has approved the import of GI maize and soya from the United States and Argentina. These commodities are milled at the port of entry and are used in food processing and animal feeds. Thus, some local processed foods containing soya and maize ingredients may be derived from GI crops.

I discovered that there are no GI fresh fruits and vegetables in South Africa and nowhere in the world are the GI foods containing animal or human genes. Finally, if you buy imported processed foods from the US, Canada, some EU countries, Argentina or China and these contain maize, soya, tomato, canola or potato ingredients they may be derived from GI crops. Don't let this worry you! The new GI foods are carefully tested for human and environmental safety. In fact, they are more tested than any of the conventional foods we eat every day.

Believing what we read

Throughout our education, we are presented with material in its written form and are encouraged to accept what we read. Unfortunately because of this, people tend to accept anything in its written form as truth, and not merely a representation of other people's opinions that may or may not be based in the truth.

The current debate about genetic modification in foods has seen a lot of printed matter both for and against this technology, with the "against" lobby being more active in the media than the "for" lobby.

There are many arguments posed for and against the use of genetic modification. People who promise benefits from biotechnology may be either completely honest, or they may have an ulterior motive for their argument. Scientist may be tempted to raise expectations too high in an effort to get research funding. On the other hand, people can be against biotechnology for similar reasons. They may belong to a group that must be seen to be conservative in the interests of the environment and their arguments may be based emotional argument and not sound science.

One has to develop critical reading skills to be able to discern the truth from a variety of sources. This does not mean that one must believe nothing one reads, or that one should suspect lies and inaccuracies in all the media. It is merely reading carefully.

The Case for Genetically Modified Crops

The advent of plant biotechnology was hailed as the engine of a Second Green Revolution, capable of providing farmers with the hardier, higher-yielding, disease-resistant and more nutritious crops needed to sustain a burgeoning world population. Plant scientists argue that modification is really nothing new; using tools such as selective breeding and hybridization, humans have been influencing the genetics of food crops for millennia. Indeed, present varieties of corn, they say, bear little resemblance to their historical progenitors. The contribution of biotechnology is that the process can be sped up enormously and new traits incorporated from virtually any species. These proponents insist that their new varieties have been more extensively tested than any in history and that their safety as foodstuffs and in the environment is well proven. All commercial genetically improved organisms must pass stringent, independent safety assessments before obtaining approval to market.

The Case Against Genetically Modified Crops

Opposition to genetically modified plants comes from many fronts. It ranges from those like biotechnology gadfly Jeremy Rifkin, who oppose gene splicing on religious and moral grounds; to environmental and consumer rights groups, including Greenpeace and the Union of Concerned Scientists, that fear unexpected consequences to the environment; to health and pure food advocates, who see the new products as adulterated; and to small farmers and organic growers, who see the products as a sign of big chemical makers, seed merchants and commercial farmers trying to force them into buying these goods or going out of business. These groups charge that there has been insufficient testing, and the benefits have not been adequately demonstrated and that there is a clear potential for ecological disaster. Moreover, they argue that the same forces that stymied earlier crops, such as acquired resistance to pesticides by insects, will also triumph over the laboratory feats of the gene splicers.

Read through the following two articles. The first article is anti-genetic modification, and the second highlights the benefits of genetic modification. Analyze each article and for each article write down the following in separate columns:

1. All the emotional adjectives used ( eg fine, fantastic, bad, disastrous, unnatural)
2. Consider the priorities of each author. What are his interests in the short and long term in respect of money, jobs, authority, and fame.
3. Which article is easier to read? Explain your answer.
4. Currently, overseas public opinion is swaying towards being against genetic modification. What role do you think the media and the anti-lobby has played in this.
5. What do you suggest can be done to allow the public a more balanced view of genetic modification?

Note: When reading it is advisable to extract facts from suppositions, possibilities from expectations as well as looking at potential consequences omitted from the article.

The Safe Food Coalition offices were flooded with inquiries after the dangers of genetically engineered (GE) foods were highlighted in the TV program Carte Blanche.

Frantic consumers wanted to find out how they could avoid these foods, says Angus Durran, spokesman for the Safe Food Coalition. The SA National Halaal Authority requested an urgent meeting with the coalition after being contacted by concerned Muslims, horrified by the implications of eating animal genes in their food.

Genetic engineering is the artificial transfer of genes from one organism to another, including transfers between organism, which would normally be impossible -like transfers from fish to tomatoes. This says Durran, poses enormous moral questions.

A spokesman for the Halaal Authority, Mr Moulana Qookay, said after their meeting, that he was going to take the matter further. At this stage, it seems that the organization would only be happy with a total ban on genetically engineered foods.

Durran says another typical call was from a distraught housewife, who was horrified to learn that she had unknowingly been feeding her baby on genetically engineered soya infant formula.

In the UK, the publicity over health concerns has persuaded six of the seven leading supermarket chains including Sainsbury, Asada and Marks & Spencer, to stop putting GE ingredients into their "own-label" foods. They also insist that all GE ingredient foods in their shops be clearly labeled.

The chairman of Iceland foods in the UK, Malcolm Walker, calls these foods "Frankenstein foods" and comments that consumers are being conned.

"The use of GE ingredients is probably the most significant and potentially dangerous development in food production this century," says Durran.

Head of Britain's Food Standard Agency, Professor Phillip James remarks, "The perception that everything is totally straightforward and safe is utterly naïve. I don't think we fully understand the dimensions of what we are getting into."

In South Africa, the SFC has been in touch with four major chain stores and thus far nothing concrete has been done regarding labeling, he says.

Pick'nPay has, however, advised us that its new specifications for house brands emphasize that products must be free of any GE foods.

"Unfortunately he government still has not acted on requests made to it by the SFC over two years ago." According to Durran, the most obvious health problems could result from the creation of novel or unexpected toxins or allergens.

"The deaths of dozens of people from eosmophilia myalgia syndrome and long term disabilities of hundreds more in 1989 have been attributed to the consumption of a food supplement (L-tryptophan) that has been produced using genetically-engineered bacteria. (This has never been conclusively proven, the manufacturers having destroyed all evidence.)

Dr H Steinmann from the Allergies Society of South Africa reported that there has been a case of a death of a person, allergic to Brazil nuts, who ate soya that was genetically-engineered with a Brazil nut gene. According to Dr John Fagan, an eminent molecular biologist, no long term safety testing has been carried out. In his book "Genetic Engineering: The hazards; Vedic Engineering: The solutions", he states that there is always the risk that genetically engineered foods may contain unintended allergens and toxins. This may be reduced in nutritional value.

He adds that GE crops may disrupt the ecosystem by reducing bio-diversity, damaging soil fertility, inducing the development of new pathogens, pests and weeds and increasing the use of toxic and carcinogenic agri-chemicals. In the UK, the government is to introduce new monitoring arrangements for foods made with genetically modified ingredients as part of a package of measures designed to calm public fears over GMO's, reports The Grocer. The developments came after a Friends of the Earth survey which showed 58% of shoppers want supermarkets to go completely GM-free.

Says Jeff Rooker, the Food Safety Minister: "All GM foods are rigorously assessed for safety before being allowed onto the market. However, the government is looking into the possibility of going even further by introducing monitoring arrangements capable of picking up any unexpected effects, should they emerge."

A new ministerial group on biotechnology and genetic modification was formed by the government. Chairman Jack Cunningham said the idea was to establish "clear and firm policies in a number of complex issues that cut across departmental boundaries and area also of great concern to the public."

The government has also decided to strictly limit farm-scale GM plantings so that they can be carefully assessed before the commercialization of GM crops in the UK. In addition, it is thinking about setting up an environmental stakeholders forum.

Note a number of inaccuracies in the last article:

• There are no animal or human genes in food crops. It produce a product that is unacceptable to vegetarians and other consumers. As such, it is unlikely that human or animal genes will ever be used in food crops and current food labelling standards would require the presence of such genes to be labelled.
• There is no need for a total ban on genetically engineered foods to address the concerns expressed by the Safe Food Coalition. For the last 15 years we have eaten many foods derived from genetic improvement, all of them safe and accepted. This ban would remove up to 60% of processed foods and drinks on our shelves today. In addition, a total ban would prevent scientists gathering the environmental safety data needed for approval for genetically improved foods. Much of this data has been requested by environmental groups that are concerned about the impact of GMOs on the environment.
• There is no detected danger to using baby foods derived from genetically improved soya, in fact, this is only soya that has undergone and passed a human safety check including safety to babies.
• Not a single health risk has been identified worldwide with any approved genetically improved food on the market to date. Why do you think that the "anti-" lobby uses safety as an issue when there is no scientific of any other proof that safety of foods can be compromised through genetic improvement? (Clue: WTO (World Trade Organization), trade restriction guidelines).
• Pick 'n Pay provides consumer information on genetically improved foods in brochures that are available in all stores. The brochures identify which foods are potentially genetically improved, should consumers have moral concerns about the technology.
• The EM syndrome, attributed to tryptophan, was caused by a purification fault and not related to the genetic technology. In fact, all tryptophan produced since the EM episode, in the USA in the 1980's, is still produced by genetically improved microorganisms and no health problems having been identified since.
• Dr Steinmann has retracted his statement about brazil nut allergens in soya, prior to publication of this article, admitting that this event never occurred. This unsubstantiated story is still being circulated by the SFC and other opponents of technology to discredit biotechnology.
• Dr John Fagan is a molecular biologist who left medical research to set up a molecular detection business. This business needs to generate a fear of genetic improvement to create a market for detection.
• The concern about toxins and allergens in foods has long been held by biotechnologists. This is why the checks for these form a major part of the human safety assessment that is carried out on all genetically improved food crops before approval is given.

Genetic Engineering of Indica Rice

Summary:

Indica-type rice provides the staple food for 2 billion people in Third World countries. Several problems involved in the stable and traditional breeding cannot solve sustained production of high quality food. Methods have been established for gene transfer to Indica rice breeding lines to study possible contributions from genetic engineering. Experiments are in progress on the development of transgenic resistance towards Yellow Stem Borer, resistance towards Rice Tungro Virus, accumulation of pro-vitamin A in the endosperm, increase of essential amino acids in the endosperm such as lysine, cysteine and methionine and resistance towards fungal pests such as Rice Blast and Sheath Blight. Transgenic clones from Indica rice breeding lines have recovered from several of the approaches mentioned some of which have been regenerated to plants.

Approach towards pro-vitamin A accumulation in rice endosperm:

According to UNICEF statistics worldwide, over 124 million children are estimated to be vitamin A deficient. Improved vitamin A nutrition could prevent approximately 1-2 million deaths annually among children aged 1-4 years. An additional 0,25-0,5 million deaths may be avoided if improved vitamin A nutrition can be achieved during later childhood. Improved vitamin A nutrition alone, therefore, could prevent 1,3-2,5 million out of nearly 8 million late infancy and pre-school age child deaths that occur in each year in the highest-risk countries. Rice in its milled form, as it is consumed by most people in South East Asia, is characterized by the complete lack of pro-vitamin A. The milled rice kernel consists exclusively of the endosperm. The aim of this project is to initiate carotenoid biosynthesis in the rice endosperm tissue to increase the daily vitamin A uptake of people predominantly living on rice.

Approach towards improvement of nutritional quality:

Milled rice not only lacks vitamins, it is also deficient in essential amino acids such as cysteine, methionine and lysine.

Concluding remarks:

The goal of our scientific work is to contribute to future sustained production of affordable and high quality food in developing countries. In this applied project, the aim is to work on problems that are a heavy burden on a great number of poor people and to apply biotechnology in such a way that it compliments traditional plant breeding. We can reach our goal only if the novel characters we introduce to Indica rice are used in breeding programs; this is guaranteed through our collaboration with IRRI. The novel characters will be successful in breeding only if they are stable and effective. This requires that we can provide breeders with a collection of many transgenic plants for each novel character to permit selection of the most appropriate individuals for the breeding program. This in turn requires more efficient gene transfer protocols than those involved to date.

Success or failure of our goal will, however, not only depend on success or failure of our experiments and successful breeding programs. It will also depend on political and social circumstances in those countries in which the novel, genetically engineered varieties are supposed to help to solve problems. Risk assessment will be an integral part of the projects. The judgement of scientists and national biosafety committees on the safety of transgenic plants or of food produced from transgenic plants however, will not necessarily lead to an acceptance of these plants or food by the local population. If we are, for example, able to produce transgenic rice that accumulates sufficient pro-vitamin A to prevent vitamin A deficiency, there is no guarantee that people would be willing to eat this rice. There is much educational and political work ahead of us in addition to what we are trying to achieve scientifically.

(from the journal Euphytica, by I Potrykus et al.)