Animal productivity and genetic diversity: Transgenic and cloned animals

Authors: Wall, Robert; LAIBLE, GOETZ - Ag Research Limited; MAGA, ELIZABETH - University Of California; SEIDEL, GEORGE - Colorad0 State University; WHITELAW, BRUCE - University Of Edinburgh

Submitted to: Council for Agricultural Science and Technology Issue Paper
Publication Type: Monograph
Publication Acceptance Date: 5/15/2009
Publication Date: 8/20/2009
Citation: Wall, R.J., Laible, G., Maga, E., Seidel, G., Whitelaw, B. 2009. Animal productivity and genetic diversity: Transgenic and cloned animals. Council for Agricultural Science and Technology Issue Paper 43, Ames, IA, pp. 16.

Interpretive Summary: Improvement in agronomic traits in all livestock species has been achieved over the past several decades using reproductive technologies. Cloning and transgenesis are the most recent of these technologies, providing geneticists with additional tools to influence population genetics. This Issue Paper describes both of these technologies, addresses their strengths and limitations, and provides a framework for discussion about their future use. Cloning is a reproductive tool that can be used to narrow or broaden genetic diversity. Somatic cell nuclear transfer is the most common method of animal cloning and is more efficient than other procedures, resulting in the use of fewer experimental animals to achieve success. Other cloning methods include embryonic cell nuclear transfer, using nuclei from cryopreserved, genetically superior cell lines, and bisecting and trisecting preimplantation embryos. The value of cloning genetically superior animals will vary depending on the situation. Cloning could increase the frequency of a desirable trait into the cattle population, for example, but because of the diverse nature of animal agriculture, it will not be possible to produce one phenotype of cattle that fits all needs. Whereas a clone is genetically identical to the animal from which it came, a transgenic animal is one into which a new gene has been introduced or in which an existing gene has been rearranged by human intervention. This technology offers potential solutions to some limitations of selective breeding while simultaneously increasing genetic diversity of populations. Applications of transgenic technology can generate animals that are better able to combat or resist infection, improve food safety and quality, increase production efficiency, decrease the environmental footprint of livestock production, and introduce new characteristics into the gene pool. The technology, however, cannot manipulate complex traits controlled by multiple genes. One of the main limitations to the development of cloning and transgenic technologies has been the lack of public acceptance. The public, for example, has been tentative to accept cloning as an animal breeding method, even though there is scientific consensus that no difference exists between food products of cloned animals and the same products of noncloned animals; this perspective recently has been supported by both a National Research Council study and by U.S. Food and Drug Administration evaluations. The authors of this paper suggest that proponents of biotechnology consider consumers’ concerns and that the government provides a regulatory process that addresses consumers’ apprehension while offering realistic expectations of biotechnology.

Technical Abstract: n/a