For centuries living organisms have been manipulated using traditional techniques such as fermentation, classical plant breeding and artificial insemination to produce new breeds, food, medicines, or other products. Although these and other newer techniques are still practiced, methods have become increasingly sophisticated during the past twenty years, with the development of a wide range of novel molecular biotechnologies. The most significant of these has been recombinant DNA or 'gene transfer' technology, which makes it possible to cut DNA from any source into fragments, and to recombine genes from widely different organisms to yield forms with specific characteristics. Traits such as herbicide resistance can be incorporated into crops to increase yields; hormones created to increase milk yield in cows; and microbes engineered to clean up oil-spills. This is what is commonly referred to as 'genetic engineering'. Genetically modified organisms are organisms whose genetic makeup has been altered by the insertion or removal of small fragments of genes or genetic material (e.g. DNA, RNA, plasmids) in order to create or enhance desirable characteristics.
Genetic engineering is often called bio-technology. This is misleading. Biotechnology uses living organisms in production processes, for example, yeast to make beer. Genetic engineering manipulates genetic material, including taking genes from one species and transferring them to another unrelated species to create new characteristics.