Genetically Modified Animals
SRT's Work on GM Animals
In the 1990's the SRT Project examined in depth the science and ethics of a range of applications of genetic modification in animals as part of its Engineering Genesis expert working group on GM crops and animals. This looked at the interface between animal research and human medicine, including human proteins in the milk of farm animals, animal cloning, xenotransplantation, and GM animals as models of human disease. In our interventions with animals, where should we draw lines and why? What would count as violating the inherent value of the animal? How far can compromises to animal welfare be said to justify human benefits? This led to the report to the 2001 Church of Scotland General Assembly GM Animals, Humans and the Future of Genetics,
We welcome the announcement that Roslin scientists have (14 January 2007) developed flocks of GM chickens with added human genes which produce potentially therapeutic proteins in the eggs. For more ... Genetically Modified Chicken Eggs for producing Anti-bodies.
Contents
Engineering Genesis
Animal Issues from the Final Reflections of SRT's Book
Other SRT Pages on GM Animals
Engineering Genesis : Animal Issues
Two chapters of Engineering Genesis are devoted to animal genetics, animal welfare and animal ethics issues, and four case studies are examined and compared.
Animal Welfare
The potential to cause harm and suffering is one of the main issues in the genetic engineering of animals. Some of the modifications made to date are detrimental to the animal, but others are neutral or even beneficial for its welfare. Examples like the oncomouse raise considerable anxieties. Attempts at genetic modification for the direct benefit of animals have not so far proved very successful. Traits like disease resistance tend to be genetically complex, and they may often be addressed better by other means. Generally speaking, genetic modification in animals has few effects on welfare which could not also be produced by selective breeding, but the latter are also increasingly being called into question. Comparison of genetic engineering with selective breeding should not assume that the status quo is an ethically acceptable or neutral ground.
Legislative safeguards need to be maintained to protect against the welfare problems which genetic engineering can bring. High welfare standards often accompany the early stages of development but attention is necessary to ensure that, when procedures become routine, commercial pressures do not then lead to a relaxation of care. The UK is in a position to influence comparable legislation in the EU. As with other areas, better public accountability and openness are required in the procedures of committees concerned with these animal issues, if public confidence is to be ensured.
Balancing Animal Ethics and Human Benefits
Three case studies of animal genetic modification for medical benefit illustrate the range of intervention in this difficult question.
Pharmaceuticals in Sheep's Milk
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Few ethical or welfare problems are raised by producing pharmaceuticals in the mik of animals. Indeed, a strong positive ethical case could be made. An animal is being put to a potentially extremely beneficial human use, with a relatively small intervention which does not compromise the animal's integrity. On the other hand, it could be argued that to engineer sheep and other mammals as living bioreactors for pharmaceutical production is an instrumental way of using the mammary function of the animal. Is this unacceptable? Humans have used animal milk as food since time immemorial, and intervened to a considerable degree in the animal's pattern of lactation and suckling its young. We already use the chemical production facility of their mammary glands to produce milk and milk products, like cheese and yoghurt, for human consumption. These adaptations of a natural function of the animal are not normally seen as ethically unacceptable. For some it is more acceptable than killing an animal for food.
On this basis, it would be hard to argue that to produce a particular protein in milk represents an inordinate change of use, especially in this case. What she produces is the human version of a protein whose sheep form she manufactures anyway. Admittedly the sheep version of the gene expresses the protein in the liver, and thence into the blood, whereas the human gene expresses in the mammary gland. The main objection would be if it was deemed unacceptable to change the animal's metabolism for any reason at all, or at least one that was not in the animal's interest. More concern might be raised if a protein were expressed in an organ or at a level which resulted in damage to the animal, as in the erythropoietin case, or a protein toxic to the animal, but these might also be ruled out on welfare grounds.
See our Press Release on Genetically Modified Chicken Eggs for producing Anti-bodies.
The Oncomouse
Genetically modifying a mouse to produce a human cancer in the animal presents a real dilemma. Potential human benefits are sought only at the cost of serious harm to the animal. In this case the seriousness of human cancer may be sufficient reason, but there is an urgent need to review the justification for the rapidly increasing scale of use of genetically modified mice models. Are realistic medical benefits being fairly adduced against the animal suffering involved; has mouse use become too routine? The dramatic increase in the overall use of model mice seems to conflict with the 'Three Rs' principle of reduction, replacement and refinement. There is a need for a culture of restraint on the use of model mice to avoid the complaint that the mice involved have been reduced to little more than material commodities.
For more see our press release on the GM Monkeys as Models of Human Disease.
Xenotransplantion
This is a novel and serious intervention in the animal kingdom, marking a change in how we relate to animals. It is different from eating them. Intuitive repulsion at the idea of having a live animal organ in one's body may convey deeper issues than mere unfamiliarity. Some of us saw it as unacceptable in principle, as a denial of the sanctity of both human and non-human life by mixing organs between species, or as an excessively instrumental use of the animal. The seriousness of intervention in the animal might, however, be justified if it offered very significant and long lasting improvement for most patients. The majority of our group took this view for the heart and kidney, given the shortfall in availability, but not as carte blanche for all organs. Breakthroughs in artificial hearts or repeated failures of xenotransplantation could tip the balance to unacceptable, as would a failure to address current concerns that xenotransplantation may provide a route to transmit serious animal diseases to the human population.
The therapeutic tools which transgenic animals may provide must never become taken for granted by the medical profession or its administrators, animal breeders, or the public. Mice must not become mere research catalogue items, sheep mere bioreactors, nor pigs spare part factories. An element of questioning must be essential in research or treatment. 'Is it really necessary to use this animal?' There are limits to how far one could go on replacing human organs, for example. Two ethical cultures both have a case – one predicated to medical treatment of serious disease as the supreme ethical goal, the other of combating the abuse of animals by humans. Neither should be regarded as absolute. A balance is implied, and it seems more likely that the current balance is weighted too far towards excessive animal use than excessive caution.
For more see our detailed article on the Ethics of Xenotransplantation
Animal Cloning
Cloning has become a cause célèbre but the animal implications have generally been overlooked in the speculation about human use of nuclear transfer technology. Cloning happens naturally in micro-organisms, fungi, algae and many plants, but not in mammals. For some people, cloning mammals would violate a biological distinction in reproduction. Moreover, were it to be routinely used in farm animals they would see this as bringing factory production concepts one step too far into animal husbandry. Others see the potential for improving breeding merit, but the need to maintain genetic diversity is likely to restrict uses to single step changes. It must be asked if the motivation justifies the intervention. Applications to animal diseases would be a less problematical goal than production efficiency. The main application of the technology at Roslin is, however, to improve methods of genetic manipulation of farm animals for specialist applications, for which the first signs are encouraging, to use less animals, and to open up a wider range of applications. Ethically it presents fewer problems, since cloning as such is a side effect rather than the aim, and the use is restricted. Welfare questions relating to pregnancy difficulties will however need to be resolved before it would be acceptable for general use. Extensions of nuclear transfer methods to mice will open a much greater range of cloning applications which will need careful ethical scrutiny.
For more see our various detailed article on Ethics of Animal Cloning
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Last updated 15 January 2007
