DNA is the substance that contains the information that determines, for example, whether your eyes are blue or brown, or whether you are tall or short. Researchers are studying the DNA in livestock so the location of important genes can be discovered. Genes that control milk production, meat toughness, and susceptibility to disease are being mapped so that in the future a simple genetic test can be used to find animals with superior qualities or resistance to disease. These animals can then be retained as breeding stock so these qualities are passed on to their offspring.
Genetic engineering involves changing the genetic makeup of an organism.
This is done by moving genes to different locations, removing them altogether, or adding genes from other organisms. When the gene transfer is from one unrelated species to another, the resulting organism is called transgenic . Genetic engineering, or recombinant DNA technology, is one of the tools biotechnology researchers use to produce better livestock. This technology uses special chemicals called enzymes to break the DNA at a particular point. A very recent advance in animal transgenics is a litter of pigs born in England whose genetic makeup has been altered with human genetic material.