Chapter 7 - Genetic Engineering
The Issues
The introduction of genetically modified (GM) crops has become highly controversial in the UK and some other parts of the world. The principal objections concern possible harm to human health, damage to the environment and unease about the 'unnatural' status of the technology. Many people in the UK object strongly to the imposition of a new and untested technology which does not appear to offer them obvious benefits. Meanwhile there are those who strongly believe that genetic modification will prove vital for securing food supplies in parts of the developing world.
The science behind the issues
Genetic engineering rests on the principle that all organisms, however different they may appear to be, have in common certain fundamental similarities at the level of their genetic material. Because of this, genes can be moved by scientists between humans and yeasts or between bacteria and plants. Furthermore, the gene operates in its new host in much the same way that it did in its old host.
What this tells us about science and society
Genetic engineering is not just science, its an industry. Industry both uses science and drives its development. Science, though, is often unpredictable, and technologies, such as genetic engineering, may have unintended consequences. Some see the motives of industry as unduly dominated by profit. People's views are coloured by the extent to which they trust statements of scientists, industrialists and politicians.
Some people acknowledge potential gains of genetic engineering, but are aware of possibly catastrophic side-affects. Adopting the 'precautionary principle', they would argue that we should err on the side of caution until risks can be more reliably assessed. Work in this area needs to be regulated. However, it can be difficult to get agreement on how this should be done.
The basic principles of genetic engineering
The whole of genetic engineering relies on the fact that the genetic make-up of all organisms is fundamentally the same. Bacteria, fungi, plants and animals all have DNA as the material that makes their genes (Zie fig. 7.2)
Genes are written in a chemical code along the length of the DNA molecules. There are four molecular 'letters' in the code and the are the same in all organisms. Because of this underlying similarity in the genetic code, it is now fairly easy for scientists to move genes from one species to another.
Suppose you want to move a gene. First, you need to identify the gene you want to move. Then you can use a special type of enzyme to cut the gene out from where it normally is and finally, you use a different enzyme to insert the gene. Basically that's it.
Now you've inserted a human gene into the DNA of a bacterium. If the gene carries the information to make insulin, the bacterium now starts making human insulin. This was developed in 1980.
Nowadays there is a variety of ways of moving genes from species to species in addition to that shown in figure 7.3. One surprisingly simple way is to fire the genes, using a tiny gun, at the organisms you want to genetically engineer. This technique is widely used for the genetic engineering of certain crops. Another way is to use a virus or a bacterium to carry the gene from one species to another. A final way is to inject the DNA into the fertilised egg of an organism.
Traditional agricultural breeding programmes
Agriculture requires four stages:
- sowing of seeds
- caring for the plants
- harvesting
- selecting and keeping back some seeds for the next generation
Traditional agriculture sometimes uses some sophisticated breeding methods. One frequently appearing technique is to cross (breed) two different varieties ( or two closely related species). Farmers then select among the offspring for the characteristics they want.
If you want to produce such new variety, it typically takes about 6 to 10 years to come up with a new crop variety using traditional breeding programmes. Genetic engineering provides a faster way of developing new crop varieties.
Applications of genetic manipulation in agriculture
Genetic manipulation is rapidly being introduced in certain crops. In 1999 around half of all soya and maize grown in the USA was genetically engineered. There are two main reasons why crops are genetically engineered: to make them herbicide-tolerant or to make them resist to pests
- Pest-resistant maize
Maize has recently been genetically engineered by a number of companies so that it produces the Bt protein of a soil bacterium. When the European corn borer larvae eat this protein, their intestinal walls are damaged, causing them to die from hunger.
- Herbicide-tolerant maize
Genetic Engineering holds out the hope that instead of researcher starting with desirable crops and then finding herbicides that kill the weeds without harming the crops, they could start with the most desirable herbicides and then genetically alter the crops so that they, unlike their weeds, are unaffected by the chemicals. Two of the most suitable herbicides are glyphosate and glufosinate. Transgenic varieties of maize have now been developed to each of these herbicides. This brings of course benefits for the farmer, environment and customer.
The farmer will probably prefer the herbicidic-tolerant maize because of the following reasons; 1) these herbicides are less expensive, 2) the crop is tolerant so the farmer will have much more choice, 3) herbicides such as these two are very affective, 4) benifits to the environment because the herbicides break down faster and benefits to the consumer on two fronts (lowered prices and a decreased risk of toxic chemicals ending up in drinking water).
Are genetically modified foods safe for humans?
Most experts agree that it's safe enough for human and animal consumption, being neither toxic nor allergenic. However some contain antibiotics which can on the longer term cause resistance for dangerous bacteria, but this chance is not very great. Testing the food is not very easy and takes a long time. Often people who consume it are monitored and then the scientists try to identify harmful consequences, even if they are very rare.
Are genetically modified crops good or bad for the environment?
Genetically modified crops are certainly not bad for the environment the only risk there is, is that they may invade natural habitats such as the oilseed rape does. Another potential problem is that genes might escape through pollen or weeds and then you might get cross varieties between wild plants and crops which may be harmful. These assessments are not straightforward, they are very important because it can be very harmful if crops invade natural habitats, this has happened with the arabidopsis plant which cross pollinates much faster when genetically engineered. Some scientists have developed mathematical models, but these may not be very reliable, although they can sometimes predict a catastrophe, like in Chernobyl.
Other current and possible future uses of genetically engineered plants and animals
Other future uses can be to insert certain vitamins and/or minerals. Another future use can be to produce plants that can produce vaccines. Instead of going to the doctor you'll then just have to eat the plant and you're immune for the disease. Nowadays genetically modified animals are mainly used for imitating certain human diseases. For these diseases certain drugs can be developed to treat it. There are a lot of people against this type of genetic engineering. These people may be a cause why less animals are being experimented with.
- Pigs for human transplants
Another reason for which animals are genetically engineered, is for human transplants. This is called xenotransplantation. The pig will be genetically engineered so, that it will have some human proteins and therefore the body won't recognize it as a pigs' organ. People tend to use pigs because of the great similarities between the organ sizes.
- Genetically engineered salmon
Salmon and other fish species are also genetically engineered for faster growth and immunity against diseases. In this way the fish prices might fall and more jobs are created.
Possible hazards of future examples of genetic engineering
The use of genetically modified animals may prove hazardous
- Pigs for human transplants
If xenotransplantation will be allowed it will be kept to very strict rules because of the risk of infection with BSE and AIDS. Also there will be very strict safety measures and the family members will be instructed about the risk and blood will be extracted from them for indefinite storage.
- Genetically engineered salmon
It's almost certain that some genetically engineered salmon escape. This may be a threat to the common Atlantic salmon and it may conquer for food and although it may not be able to breed with the wild fish, it might breed with other fish species and it's also known that the genetically engineered salmon reproduce in the Atlantic.
Ethical issues raised by genetic engineering
Of course people ask themselves whether it's right that we use pigs for xenotransplantation. This is a very ethical question to which there may be various different answers, although the pigs are extremely well looked after, some people find it morally wrong to use pigs for xenotransplants. Also people ask is it natural and of course the answer is No. In nature no pig would ever carry human genes, but is everything what's unnatural bad? That kind of questions don't have an answer. It's an opinion for which you have to give arguments.
Do people want genetic engineering?
There are some questions you have to ask yourself before answering it, like: are atibiotic-resistance genes necessary? Will GM foods be cheaper? Will small farmers be forced out of business? Will GM crops be good or bad for wildlife? Is it morally acceptable? Is genetic engineering 'playing God'? All questions which people answer differently.
How is genetic engineering regulated?
In the case of the regulation of GM crops in the UK, there are a considerable number of committees and other groups involved.( Ik zou ff kijken op pagina 100 figure 7.14 dan zie je ze allemaal staan) Of central is who is appointed to these committees. For example the ACNFP( Advisory Committee on Novel Foods and Processes) is the committee which recommends to government ministers whether new foods, including all GM crops should be approved. All but two of the members are scientists, several with links to the food industry.
Key terms
Genetic engineering usually means moving genes from one species to another. The term also covers the insertion into organisms of artificial genes - i.e. genes made in the laboratory. Other terms for genetic engineering include 'genetic modification' 'genetic manipulation' and 'recombinant DNA technology'. Genetically engineered organisms are sometimes referred to as 'transgenic organisms'.
Biotechnology is the application of biology for human purposes. It involves using organisms to provide us with food, clothes, medicines and other products. Traditional biotechnology includes the breeding of crops and farm animals and the use of yeast in cheese-making, brewing and whine production. Modern biotechnology uses such techniques as genetic engineering, cloning and embryo transfer.
Agriculture means the growing of plant crops such as wheat, maize, rice, potatoes and melons.
The Issues
The introduction of genetically modified (GM) crops has become highly controversial in the UK and some other parts of the world. The principal objections concern possible harm to human health, damage to the environment and unease about the 'unnatural' status of the technology. Many people in the UK object strongly to the imposition of a new and untested technology which does not appear to offer them obvious benefits. Meanwhile there are those who strongly believe that genetic modification will prove vital for securing food supplies in parts of the developing world.
The science behind the issues
Genetic engineering rests on the principle that all organisms, however different they may appear to be, have in common certain fundamental similarities at the level of their genetic material. Because of this, genes can be moved by scientists between humans and yeasts or between bacteria and plants. Furthermore, the gene operates in its new host in much the same way that it did in its old host.
Genetic engineering is not just science, its an industry. Industry both uses science and drives its development. Science, though, is often unpredictable, and technologies, such as genetic engineering, may have unintended consequences. Some see the motives of industry as unduly dominated by profit. People's views are coloured by the extent to which they trust statements of scientists, industrialists and politicians.
Some people acknowledge potential gains of genetic engineering, but are aware of possibly catastrophic side-affects. Adopting the 'precautionary principle', they would argue that we should err on the side of caution until risks can be more reliably assessed. Work in this area needs to be regulated. However, it can be difficult to get agreement on how this should be done.
The basic principles of genetic engineering
The whole of genetic engineering relies on the fact that the genetic make-up of all organisms is fundamentally the same. Bacteria, fungi, plants and animals all have DNA as the material that makes their genes (Zie fig. 7.2)
Genes are written in a chemical code along the length of the DNA molecules. There are four molecular 'letters' in the code and the are the same in all organisms. Because of this underlying similarity in the genetic code, it is now fairly easy for scientists to move genes from one species to another.
Suppose you want to move a gene. First, you need to identify the gene you want to move. Then you can use a special type of enzyme to cut the gene out from where it normally is and finally, you use a different enzyme to insert the gene. Basically that's it.
Now you've inserted a human gene into the DNA of a bacterium. If the gene carries the information to make insulin, the bacterium now starts making human insulin. This was developed in 1980.
Nowadays there is a variety of ways of moving genes from species to species in addition to that shown in figure 7.3. One surprisingly simple way is to fire the genes, using a tiny gun, at the organisms you want to genetically engineer. This technique is widely used for the genetic engineering of certain crops. Another way is to use a virus or a bacterium to carry the gene from one species to another. A final way is to inject the DNA into the fertilised egg of an organism.
Traditional agricultural breeding programmes
Agriculture requires four stages:
- caring for the plants
- harvesting
- selecting and keeping back some seeds for the next generation
Traditional agriculture sometimes uses some sophisticated breeding methods. One frequently appearing technique is to cross (breed) two different varieties ( or two closely related species). Farmers then select among the offspring for the characteristics they want.
If you want to produce such new variety, it typically takes about 6 to 10 years to come up with a new crop variety using traditional breeding programmes. Genetic engineering provides a faster way of developing new crop varieties.
Applications of genetic manipulation in agriculture
Genetic manipulation is rapidly being introduced in certain crops. In 1999 around half of all soya and maize grown in the USA was genetically engineered. There are two main reasons why crops are genetically engineered: to make them herbicide-tolerant or to make them resist to pests
- Pest-resistant maize
Maize has recently been genetically engineered by a number of companies so that it produces the Bt protein of a soil bacterium. When the European corn borer larvae eat this protein, their intestinal walls are damaged, causing them to die from hunger.
- Herbicide-tolerant maize
The farmer will probably prefer the herbicidic-tolerant maize because of the following reasons; 1) these herbicides are less expensive, 2) the crop is tolerant so the farmer will have much more choice, 3) herbicides such as these two are very affective, 4) benifits to the environment because the herbicides break down faster and benefits to the consumer on two fronts (lowered prices and a decreased risk of toxic chemicals ending up in drinking water).
Are genetically modified foods safe for humans?
Most experts agree that it's safe enough for human and animal consumption, being neither toxic nor allergenic. However some contain antibiotics which can on the longer term cause resistance for dangerous bacteria, but this chance is not very great. Testing the food is not very easy and takes a long time. Often people who consume it are monitored and then the scientists try to identify harmful consequences, even if they are very rare.
Are genetically modified crops good or bad for the environment?
Genetically modified crops are certainly not bad for the environment the only risk there is, is that they may invade natural habitats such as the oilseed rape does. Another potential problem is that genes might escape through pollen or weeds and then you might get cross varieties between wild plants and crops which may be harmful. These assessments are not straightforward, they are very important because it can be very harmful if crops invade natural habitats, this has happened with the arabidopsis plant which cross pollinates much faster when genetically engineered. Some scientists have developed mathematical models, but these may not be very reliable, although they can sometimes predict a catastrophe, like in Chernobyl.
Other current and possible future uses of genetically engineered plants and animals
Other future uses can be to insert certain vitamins and/or minerals. Another future use can be to produce plants that can produce vaccines. Instead of going to the doctor you'll then just have to eat the plant and you're immune for the disease. Nowadays genetically modified animals are mainly used for imitating certain human diseases. For these diseases certain drugs can be developed to treat it. There are a lot of people against this type of genetic engineering. These people may be a cause why less animals are being experimented with.
- Pigs for human transplants
- Genetically engineered salmon
Salmon and other fish species are also genetically engineered for faster growth and immunity against diseases. In this way the fish prices might fall and more jobs are created.
Possible hazards of future examples of genetic engineering
The use of genetically modified animals may prove hazardous
- Pigs for human transplants
If xenotransplantation will be allowed it will be kept to very strict rules because of the risk of infection with BSE and AIDS. Also there will be very strict safety measures and the family members will be instructed about the risk and blood will be extracted from them for indefinite storage.
- Genetically engineered salmon
It's almost certain that some genetically engineered salmon escape. This may be a threat to the common Atlantic salmon and it may conquer for food and although it may not be able to breed with the wild fish, it might breed with other fish species and it's also known that the genetically engineered salmon reproduce in the Atlantic.
Ethical issues raised by genetic engineering
Of course people ask themselves whether it's right that we use pigs for xenotransplantation. This is a very ethical question to which there may be various different answers, although the pigs are extremely well looked after, some people find it morally wrong to use pigs for xenotransplants. Also people ask is it natural and of course the answer is No. In nature no pig would ever carry human genes, but is everything what's unnatural bad? That kind of questions don't have an answer. It's an opinion for which you have to give arguments.
There are some questions you have to ask yourself before answering it, like: are atibiotic-resistance genes necessary? Will GM foods be cheaper? Will small farmers be forced out of business? Will GM crops be good or bad for wildlife? Is it morally acceptable? Is genetic engineering 'playing God'? All questions which people answer differently.
How is genetic engineering regulated?
In the case of the regulation of GM crops in the UK, there are a considerable number of committees and other groups involved.( Ik zou ff kijken op pagina 100 figure 7.14 dan zie je ze allemaal staan) Of central is who is appointed to these committees. For example the ACNFP( Advisory Committee on Novel Foods and Processes) is the committee which recommends to government ministers whether new foods, including all GM crops should be approved. All but two of the members are scientists, several with links to the food industry.
Key terms
Genetic engineering usually means moving genes from one species to another. The term also covers the insertion into organisms of artificial genes - i.e. genes made in the laboratory. Other terms for genetic engineering include 'genetic modification' 'genetic manipulation' and 'recombinant DNA technology'. Genetically engineered organisms are sometimes referred to as 'transgenic organisms'.
Biotechnology is the application of biology for human purposes. It involves using organisms to provide us with food, clothes, medicines and other products. Traditional biotechnology includes the breeding of crops and farm animals and the use of yeast in cheese-making, brewing and whine production. Modern biotechnology uses such techniques as genetic engineering, cloning and embryo transfer.
Agriculture means the growing of plant crops such as wheat, maize, rice, potatoes and melons.
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