Transgenic animals in agriculture and medicine
Languages of publication
One of the most important issues in the use of transgenic technology in animal breeding is production of meat. For that purpose growth enhancing DNA sequences are introduced to the genome of pigs, sheep, cattle, rabbits and fish. The structural elements of the introduced genes usually GH, GRF or IGF-I, which are combined with the regulatory elements. In the case of transgenic swine, the higher growth rate, and the lower fat content were achieved by using these gene constructs. However, a number of such swines were sterile and had some other pathological problems. Similar and even more serious problems, were noticed in the case of transgenic sheep up. To date, most transgenic livestock projects focused on enhancing growth in farm animals by overexpressing growth hormone have to pathological changes in transgenic farm animals; only in transgenic fish no such problems have been ecountered. Fast growing transgenic trouts, carps and salmons carrying the so called 'all fish gene constructs' could be used even right now as food. Another goal in transgenic livestock projects is manufacturing of biologicaly active human proteins in the mammary gland. Transgenic sheep, goats, pigs and cows which produce human pharmaceuticals in their milk have been obtained. Some of such proteins undergo clinical trials. In another arena, it is planned to modify the milk of ruminants in order to obtain better product, which will be used in the dairy industry. It is possible to introduce more copies of milk protein genes into the genome, 'improving' the existing genes, or to inhibit the expression of some genes - thus reducing or eliminating the production of unwanted proteins. Another way to modify milk composition is the so called 'humanisation' of cow's milk by changing the proportion of cow's to human proteins. So far, all these modifications in the area of milk proteins are done mostly on laboratory animals and the introduction of these possibilities to farm animals would be desirable. Except for fish, transgenic farm animals are relatively safe to the environment; the probability of transgenic animals surviving and reproducing out of farms is rather very low. On the contrary, introduction of highly productive farm animals (cows, pigs) to breeding would be profitable to the environment and the called 'transgenic bioreactors' would also cause decrease of chemical or pharmaceutical industry contamination to the environment. For consumers, the products obtained from transgenic animals should be safe. 'Transgenic' products, which normaly exist in the nature, are not more unsafe than their natural counterparts. There is a clear consumer demand for testing all new products which normaly do not exist in the nature, i.e. proteins with totaly new amino acid sequence, before their introducing into the market. However, this is also valid for all novel food products, not only those obtained by biotechnology.
Publication order reference
S.J. Rosochacki, Instytut Genetyki i Hodowli Zwierz?t PAN, Jastrzebiec, 05-551 Mrokow, Poland