Recombinant DNA, gene transfer and the future of animal agriculture.

Recombinant deoxyribonucleic acid (DNA) technology and gene transfer are two areas of biotechnology that will have significant impact on animal agriculture. Applications to animal agriculture can be expected in animal health management, improved crops and feeds, manipulation of animal physiology, and genetic improvement of livestock species. Improved diagnostic reagents and vaccines that will improve herd health are currently under development. Yield of crop plants such as corn will be increased and the nutritional value of these feeds improved through applications of recombinant DNA technology. Administration of exogenous hormones synthesized by bacteria holds great promise for increasing the yield of milk and possibly meat. Research on the transfer of cloned genes into animals has progressed rapidly and has recently been accomplished in sheep and swine. Tissue-specific and developmentally regulated expression of transferred genes now seems possible with defined gene promoter sequences. Several applications of these biotechnologies can be expected within 5 to 10 yr, whereas others may require longer periods of research. The 21st century will herald a new era in animal science research and applications, with recombinant DNA and gene transfer playing major roles.