What Are Four Risks Associated With Genetically Engineered Animals?

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9. RISK FACTORS OF GMOS

In that location are a number of publications which address this outcome. Maclean and Laight (2001) and Dunham (1999) accept produced very useful reviews which discuss many of the points raised in this paper.

In our view the most important areas of risks which need to be considered in the use of transgenics are:

ane. human health
2. biodiversity
3. animal welfare
4. poor communities

In each of these categories there exists a multiplicity of pathways past which effects could, in principle, be brought virtually. Rational and responsible assessment of risk requires that the following backdrop are all considered:

ane. source of the DNA of the target factor;
2. source of the non target DNA segments of the construct used;
3. site(due south) of incorporation of the transgene within the recipient genome;
iv. product of the transgene;
5. interaction of the transgenic product with other molecules in host and consumer;
half dozen. possible molecular changes in transgene production during processing;
7. pleiotropic furnishings of transgene;
8. tissue specificity of transgenic expression; and
9. numbers of transgenic organisms capable of interacting with natural systems).

ix.1 Human health

The risks to health will depend upon all of the factors listed in a higher place. In practical terms the most important of these are likely to be the source of the Deoxyribonucleic acid and the nature of the product.

The nifty majority (98 percentage) of dietary DNA is degraded by digestive enzymes relatively quickly (Purple Society, 2001) only utilize of viruses (disarmed or otherwise) every bit vectors, must increase the take a chance factor significantly every bit these are organisms which are adapted to integrating into host genomes and some represent risk factors for cancer induction. The piece of work of Zhixong Li et al. (2002) who induced leukaemia by using retroviral vectors in making transgenics for a unremarkably used marking gene in mice and a recent written report of leukaemia induction in a child undergoing gene therapy for x-SCID using a retrovirus (Hawkes, 2002) show that this is non a trivial risk. Arguments about risks and benefits attached to this form of factor therapy are current (Kaiser, 2003).

At the other extreme the use of autotransgenics must exist seen every bit posing a risk which is orders of magnitude lower than that for allotransgenics and probably negligible. The major risk from the product of the transgene will lie in the use of novel proteins or other molecules produced by the transgenic organisms. Either in the native grade or, post-obit modifications in the human body, such molecules could be inimical to human health (e.thousand. through allergies). Information technology would seem sensible to avoid the use of such substances except where strictly necessary and under rigorous control.

Other potential risks may lie in incorporation of transgenic DNA into the genomes of resident gut microflora (though this is likely to be very improbable) or a modify in the pathogen spectrum of the transgenic fish leading to information technology hosting a new pathogen which happens to be also a human pathogen.

Maclean and Laight (2000) assessed risks to consumers as "very low".

9.2 Biodiversity

The extent of aquatic diversity is both extremely large and relatively poorly understood (Beardmore, Mair and Lewis, 1997). This means that the task of estimating the risks to aquatic biodiversity at all of its levels from the utilise of GMOs or indeed, any genetically distinctive strain used in aquaculture is monumentally large. Aquaculture has a further trouble in that the (most ever unintended) escapes of genetically distinct farmed fish are unpredictable and often large in numbers. Stenquist (1996) in discussing transgenics in open body of water aquaculture, quotes some relevant figures. Thus, 15 percentage escapes for Atlantic salmon, escapes of 150 000 salmon and 50 000 trout in Republic of chile and catch statistics for Atlantic salmon off Kingdom of norway in which 15?xx percent of the fish caught were of farmed origin. In Scotland an escape of 100 000 Atlantic salmon was reported recently. It is clear that escapes of these magnitudes pose considerable issues and it is not surprising that in some parts of Norway fish of farmed origin represent a bulk of the animals fished (Saegrov et al., 1997)

The major focus of attending in the literature lies, understandably, upon the furnishings of escapes upon natural populations of the aforementioned species, only we must ever deport in heed possible impacts beyond an assemblage or ecosystem equally a whole. The first general point to make is that there is, in principle, no difference between the biodiversity risks from escapes of GMOs and from fish genetically improved in some other mode, east.g. by selective convenance or (in some respects) from exotic species.

The second general principle is that such genetically improved forms including GMOs, are developed for a specific set of environmental circumstances in which they enjoy an advantage conferred by human decisions. In nature, notwithstanding, such genetically singled-out forms may legitimately be regarded as mutant forms of the wild type. A considerable body of genetical cognition tells us that the probability of survival of mutant forms is extremely low considering they are disadvantaged in viability and/or fertility under natural conditions. Thus, for case, in the genetically distinct farmed Atlantic salmon in Norway the males are very much less successful than wild males in securing mates (Jonssen, 1997).

However, information technology must be conceded that in species like salmon where the farmed populations outnumber the wild populations by orders of magnitude, the effects of escapes of any genetically distinct genotype upon natural populations may be both deleterious and of pregnant size simply equally a event of "swamping"

An interesting model of the furnishings on a medaka (Oryzias latipes) population of transgenic release has been produced past Muir and Howard (2001) using estimates of juvenile and adult viability, age at sexual maturity, female fecundity, male person fertility and mating advantage. They were able to demonstrate that the transgene would spread in natural populations, despite low juvenile viability, if transgenes have sufficient high positive furnishings on other fettle components. Information technology has been argued that this might pb to extinction merely the selective pressure for recombinant genomes with college viability would be expected to be immense.

Maclean and Laight (2000) simulated the changes in frequency of a transgene expected with different scenarios embracing a range of selective values including heterozyote reward. They note that "repeated small introductions [of the transgene] tin can have an effect on ... frequency ... since the frequency of advantageous alleles rises much more quickly than if a unmarried large introduction is considered".

A major trouble in assessing risk to natural populations is that of scale. Even if farmed fish are at a selective disadvantage in natural conditions, the ratio of wild:farmed numbers may in some areas, be relatively small. In these situations meaning modification of the "native" population and its function in the ecosystem is inevitable.

Whilst not providing a completely satisfactory answer, there is little doubtfulness that making farmed fish sterile would go a long style towards reducing the pressure upon such threatened ecosystems. A number of enquiry efforts to develop systems for sterile fish production are beingness made. The techniques include triploidisation, antisense transgenics, ribozymes and gene targeting (Maclean, 2002; Uzbekova et al., 2001; Maclean, pers. com.).

Provided that the all-time containment measures (physical and biological) are adopted, in our opinion, in general risks to biodiversity by GMOs per se are probably extremely pocket-size, but in specific cases, the risks and consequences may be large. As a full general dominion and adopting a precautionary approvah (OECD, 1995), it is, however, clear that each private case needs careful written report and appraisal and the best possible containment measures before approving for uptake into commercial production is given.

9.3 Animal welfare

The direct or indirect effects of transgenesis upon the welfare of fish GMOs in aquaculture are very poorly understood. In role, no doubt, this is because notions of brutal or unnatural treatment in mammalian species translate, for a variety of reasons, imperfectly to fish. Nevertheless, as life forms with highly adult nervous systems and with a range of behavioural phenotypes which flow from this, fish qualify for welfare consideration.

There are a few studies which deport on this. Thus, for example, Devlin et al. (1995b) reported changes in colouration, cranial deformities and opercular overgrowth and lower jaw deformation in coho salmon transgenic for AFP and GH. After one year of development anatomical changes due to growth of cartilage in the cranial and opercular regions were more severe and reduced viability was evident.

The larger body of data on species farmed terrestrially shows dysfunctional evolution leading to acromegaly, lameness and infertility in some GH transgenics in pigs and sheep. However, in pigs dietary modification influencing nutritional levels of zinc proved successful in avoiding such abnormalities (Pursel and Solomon, 1993; Pursel, 1998).

We take been unable to find systematic data on the incidence, in fish GMOs, of effects such as those described past Devlin et al. (1995b) and this is probably because animal welfare is non sufficiently widely recognised every bit an issue in relation to the use of GMOs. This is well illustrated in the otherwise comprehensive and balanced review by Sin (1997) in which the section on ethical issues contains no reference to fauna welfare. Nevertheless, if GMOs are to be used in aquaculture (and there are weighty arguments for so doing), concerns on this issue will need to be properly satisfied. The Royal Society report (2001) devotes a significant amount of space to this outcome.

nine.4 Poor communities

This term rather than poor countries is used because all poor countries contain rich people and rich communities. The possible economic disadvantages of use of transgenics eye on 2 issues:

nine.iv.1 Dependence on external agencies for seed fish

If transgenic fish become widely grown because they are much more efficient, and if special broodstock are required to produce fry for on-growing to adults, which, cannot be used equally broodstock, a dependency is created. This dependency may be benign or oppressive, depending on the arrangements made for seed supply.

ix.4.two Intellectual property rights

This is a very hard effect indeed. Since genes may at present be patented and therefore, savor commercial value, the opportunities for dispute well-nigh equitable treatment of stakeholders in cases where ownership of genes and strains is contested, are legion.

A recently published report (Committee on Intellectual Property Rights, 2002) states that developing countries are ofttimes disadvantaged in the use of, and access to, IPR considering of increasingly protective attitudes taken by owners of IPR. However, the report also indicates that developing countries are very heterogeneous in respect of their power to use and develop IPR.

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Source: https://www.fao.org/3/y4955e/y4955e0a.htm

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