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O10. Human beings can alter the genetic composition of organisms.


Student Outcome: O10.1

Give examples of how human beings use genetic engineering to produce organisms and substances of benefit to them.


Genetic modification, or genetic 'engineering'a of animals involves the addition or deletion of part of the genetic code (DNA) of an animal in order to change the animal's characteristics (its phenotype). Change in phenotype can be brought about either through expression of introduced DNA, or through addition, deletion or substitution of some part of the animal's own genetic material. The aim is usually that the genetic alteration should also be present in the germ line cells, so that the changes can be passed on from generation to generation.


A range of methods is available for altering the genetic material. Techniques include pro-nuclear micro-injection (available since 1980, and used in a range of species); embryonic stem cell manipulation (in mice, and very recently, primates); and (also recently) the ability to modify farm animals by nuclear transfer (1,2).


This paper is concerned with non-human vertebrate animals, which are genetically modified and used


  • in research and testing (e.g. in studying gene function and regulation, as models of human disease and in toxicity testing);


  • to synthesise medically important proteins;


  • in developing animals which might, in future, be used as sources of organs and tissues for xenotransplantation;


  • as farm animals modified to have increased 'productivity' or disease resistance.


Source: http://www.boyd-group.demon.co.uk/genmod.htm


Pretty dry introduction into the use of bacteria in genetic engineering

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This is a quick introduction to how restriction enzymes add genes to plasmids.


Go here: sorry can't embed it yet!


A reintroduction to protein synthesis and thence to the Human Genome Project - good for revision

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Student Outcome: O10.2

Discuss ethical issues associated with the genetic manipulation of organisms.


Fundamental moral objections

  • Objections to the use of animals in general


Most people, nowadays, would agree that animals can have 'interests' (interests not to be caused pain and suffering, for example), but there is considerable debate about whether,and to what extent, these interests may be forfeited for human interests. Many arguments (about consciousness, self-consciousness, cognitive ability, language capacity, moral sense, quality of life, and evolutionary status, for example) have been used in attempts to find morally relevant differences (or, conversely, similarities) between humans and animals which could justify (or preclude) treating animals as means to human ends. None of these arguments so far has succeeded in attracting general philosophical agreement.


There is a spectrum of opinion regarding the relative weightings that should be accorded to human and animal interests. At the ends of the spectrum are the absolutist positions - that human interests are always sufficiently important to outweigh animal interests, or that they are never sufficiently important. The latter view, at its simplest and strongest, is that if it is wrong to conduct certain experiments on humans, it is also wrong to conduct them on animals. This moral position is not negotiable, although the animal interests focused on may differ. For example, some animal welfarists object to any experiment which causes animals pain and suffering, whereas some advocates of animal rights object to all human uses of animals, whether or not pain and suffering is involved.


  • Objections to the genetic modification of animals in particular


A different kind of moral objection is specifically concerned about the nature of genetic modification. The concern may be expressed, for example, by objecting that genetic engineering is 'unnatural', that it amounts to 'playing God', and that it 'debases animals' by treating them as 'commodities'. A related view is that there are special moral objections to the creation of animal strains which suffer throughout their lives because of their genetic make-up.


  • Concerns about the consequences of genetic modification of animals


The argument that it is acceptable to use animals as means to at least some human ends usually appeals to the benefits of that use - that, in at least some cases, the benefits of using animals can outweigh the harms that are caused. Here, therefore, the main ethical concerns are about the consequences. In the case of genetic modification, there may be concern about consequences for the welfare of modified animals, and about the harms caused during their production. There may also be concern about the hazards which modified organisms might pose to human and animal health and to the environment. Or, again, there may be concern about the balance of harms and benefits arising from genetic modification.




Fundamental moral objections to genetic modification may be expressed in the argument that genetic engineering 'fails to respect the genetic integrity' of animals, because it involves 'mixing' of genetic material between different species and even between different Kingdoms (between animals and plants for example)b. Anxiety, distaste, or even revulsion, may be expressed about the 'unnatural' mixing of kinds - about creating chimeras, about altering the 'telos' of species (so as to interfere with a pig's 'pig-ness', for example), about crossing the species barrier, and about the mixing of genes between humans and other animals. These moral objections may arise, for example, from widely held philosophical or religious world-views, or from deep-seated emotions or aesthetic values. (Associated with these fundamental objections may be consequentialist fears that limited experiments in such areas can lead down 'slippery slopes', perhaps culminating ultimately in ethically indefensible human eugenic practices, or creating bizarre animals and/or treating animals as mere commodities.)


In response to these objections it can be argued that talk of 'mixing' genomes does not reflect the nature of genetic engineering as currently practised. Although there is a random element, present practice usually involves the relatively precise transfer of only one or two genes - a small fraction of the genome of most recipient organisms (which may contain upwards of 100 000 genes). Each gene codes for a specific protein, and it is only the combined effects of expression of a multitude of genes within the living organism that confer, say, its 'pig-ness' or its 'human-ness'. Furthermore, many genes are conserved (are similar) between different species.


However, transfer of, for example, even a single human gene into a pig can result in expression within that pig of something typically human - a human protein, such as human growth hormone. The human protein may be only very slightly different from the pig protein but nevertheless it is found naturally only in humans. Furthermore, whilst currently it is feasible to transfer only a few genes between species, in future it may be possible to transfer many more genes - and we therefore need to be alert to the biological implications and related ethical concerns that might arise.


Good if amateur introduction into genetic engineering and some of it's implications:

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