ANIMAL AND PLANT GENETIC ENGINEERING
Contents
How Genetic Engineering is being Developed
Some Ethical Questions
Some Wider Questions
SRT's Other Pages on Genetic Engineering in Animals and Plants
Further Information
Other SRT Project Pages
Animal and Plant Genetic Engineering
Genetic engineering has been performed for centuries in animals and plants by selective breeding. This enhances particular genetic traits based on outward appearance, by choosing, for example, which boars to mate which sows to develop, over many generations, leaner pig meat. From the early beginnings in the 1970's, however, it has now become possible to manipulate specific genes at a molecular level, using laboratory procedures on material taken from living organisms, which can be replaced in the organism, or put into a different one. In principle, this ought to be much more specific than selective breeding, but the uptake of the relevant modified gene is often quite low, particularly in animals. It also allows the creation of "transgenic" organisms, where a short section of genetic material from an unrelated species can be introduced into another (N.B. a transgenic animal does not mean a 50-50 mixture!).
This page is just a sampler to give the flavour of the issues. In November 1998, Earthscan published our new book Engineering Genesis
Genetic Engineering in Animals
With some notable exceptions, it has not proved as straightforward to produce "transgenic" animals as originally thought, but various manipulations have been performed, many of which are still at a fairly early stage of development. Human growth hormone was introduced in mice and pigs in early experiments, but many problems were found and this work has mostly been discontinued. In general, attempts to genetically engineer farm animals to enhance production - more specifically and rapidly - have not been promising. At present the best prospects for this type of "production" genetic engineering seem to be mainly in fish. Most of the applications of genetic engineering in animals have been in finding novel uses for the animal.
By far the largest of these has been in producing transgenic mice to "model" human diseases. Sufficient similarity has been found that once a human gene has been identified, one of the easiest ways to find out its function is to disable the equivalent gene in a mouse and observe the effect. Alternatively mice have been produced which contain a genetic defect which is likely to produce the symptoms of a human disease, like cycstic fibrosis and many fomrs of cancer. The first and most famous (or infamous) of these was the Harvard "oncomouse", a mouse engineered to develop a cancer for use in testing potential cancer drugs. This caused immense controversy when the mouse became the subject of a patent application. Partly this was over the patenting of an animal as such, and partly because of the inevitable suffering which the animal would undergo. A long-awaited hearing at the European Patent Office in Munich in late November will decide whether a series of moral and ethical objections to the patent will be upheld.
Generally less controversial has been the novel idea of genetically engineering mammals so that in their milk they produce proteins of potential medical benefit as pharmaceutical products. The leading example of this is the production of alpha-1-antitrypsin in the milk of a sheep called Tracy and her progeny in Edinburgh. Sufferers from the lung disease emphysema have a defficiency of this protein, and this method is being developed as a convenient source of it in fairly large quantities, which appears to have no ill effects on the sheep and which has the prospect of being safe from the cross contamination which can arise if human blood is used as the source. The preliminary clinical trials are awaited. Other applications are being attempted using the same basic idea in Edinburgh and elsewhere.
A third novel area is to xenografting - the potential use of animal organs as transplants into humans, such as hearts and kidneys - where there is a significant shortfall between patients and realistic potential donors. By genetically engineering a pig's heart with a human gene, researchers at Cambridge hope to produce a "layer" of proteins around the heart which would send the signal "human". This might be able to convince the human body not to put into action the rapid rejection of tissue belonging to another species. No one knows whether this will be successful. There would still remain a number of other problems to be solved, including the need to supress the body's slower rejection that is familiar in human-human heart transplants. For more this issue, see our page on
Xenografting
Genetic Engineering in Plants and Food
This is a much easier area technically, which is reflected by the wide array of applications which are being used and being developed.
- Diseases and herbicide resistance in crops (though cereals are less easy)
- Tolerance of environmental extremes in crops - drought, cold, salinity, flooding, aluminium.
- Yield improvement - not generally very good, except potatoes!
- Quality improvement - successful in Lucerne and clover (of value to sheep's wool)
- Food quality - non-squashy tomato - easier transport and storage without losing flavour.
- Manufacture of pharmaceutical products in plants using modified plant viruses
- Biofuels and bioplastics are being developed from genetically engineered oil seed rape and other crops, as substitutes for fossil fuels, which should not worsen the Greenhouse effect.
This has also become an area of high controversy. For more about the issues involved, see our pages on
Genetically Modified Food
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This is all very well, but what are the ethical questions?
Here are a few of the issues for animals and plants.
- Is genetic manipulation of animals and plants inherently wrong, or permissible under some circumstances? In either case, why?
- Consider the series micro-organism-plant-animal-human. Should we draw a line limiting genetic manipulation at some point? If so where, and on what grounds?
- Which potential benefits, if any (e.g. therapeutic medicines), might be thought to justify animal genetic manipulation, which would not? What criteria might we apply?
- In what sense does genetic modification by biochemical methods differ ethically from age-old selective breeding practices? Are we exceeding ethical limits even in selective breeding?
- What constitutes proper and improper human use of animals? Should animals ever be used in research? Do animals have "rights", as we think of "human rights"?
- Should animal organs, e.g a pig's heart genetically modified to counteract tissue rejection, be transplanted into humans to overcome the large and inevitable shortfall in donor organs?
- Should we eat foodstuffs which had been genetically manipulated using human genes? Why, or why not? How does this affect religious and other groups with strong dietary laws?
- Should anyone be able to patent a genetically modified animal or plant? If not, how else could a company protect the results of a huge research programme?
- Is the profit motive too dominant a driving force in research in biotechnology? What other criteria are important? Are we reducing animals, and nature in general, to the status of just commodities?
- What other system of funding might you apply?
- How great are the potential risks involved in releasing genetically modified organisms into the biosphere without knowing all the possible consequences?
- Is genetic engineering to make a staple crop more resist in marginal conditions (e.g. drought, cold) a potential boon for Third World agriculture, or another danger of increased dependence on rich "developed" countries?
- How should we handle an emotive issue about which opinions are apt to be polarised at a very fundamental level? How do you assess a "gut reaction" ethically?
- It is an "expert technology", but how do we make the "experts" accountable to society?
- How should the public be represented in what goes on?
- How do we handle issues of information and misinformation, the media and lobbying?
- How far should commercial secrecy be allowed, and how far should a firm be obliged to publish?
- What are our motives in genetic engineering? - commercial, humanitarian, curiosity, professional kudos, national interests, to improve mankind, ...?
- Are there better medical or biotechnical things to be doing with our research money than genetic engineering?
- Is someone somewhere always going to do the unethical thing, whatever we say?
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To address all these issues would not take a web page or two but an entire book! And that is exactly what we have done. We are proud to announce the publication in September of our major new book. For the past 4 years we have has an expert working group looking at the knotty questions in this rapidly growing field. The Working Group comprised senior scientists working in the field as well as specialists in ethics, theology, sociology, public perception and risk. This multi-disciplinary approach is central to SRT's work. It has enabled us to present a unique perspective balancing different viewpoints, and examining the wider social implications as much as the ethical issues.
We can't put the whole book on the web, but we have a Preview and Contents as well as pages covering some key issues :
Genetically Modified Food
Xenografting
Patenting
and of course our extensive pages on Cloning.
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Genetic Engineering Introductory Page
What is Genetic Engineering?
Engineering Genesis - SRT's Book and Study on Genetic Engineering
The Working Group which produced "Engineering Genesis"
Animal and Plant Genetic Engineering page
Genetically Modified Food
Xenotransplantation
Patenting Life?
SRT's Pages on Human Genetics
Human Genetics
Gene Therapy
SRT's Pages on Cloning
Cloning
This page has been produced by the Society Religion and Technology Project of the Church of Scotland. For more about our work on other issues, see our Other SRT Project pages, or our SRT Publications List.
We'd also welcome any comments you may have. We don't claim to have said the last word!
If you want to send us a comment or obtain further information or receive our latest Newsletter,
email us at :
mailto:srtp@srtp.org.uk
or send an ordinary letter or fax to :
Dr.Donald M.Bruce,
Society, Religion and Technology Project,
, 121 George Street, Edinburgh, EH2 4YN, Scotland.
tel. +44 (0)131-240 2250, fax +44 (0)131-240 2239,
email address : srtp@srtp.org.uk
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