Genetic engineering, or recombinant DNA technology, has only developed in the past decade or so; it is the process of changing the genetic material of a cell (see CELLS). GENES from one cell – for example, a human cell – can be inserted into another cell, usually a bacterium, and made to function. It is now possible to insert the gene responsible for the production of human INSULIN, human GROWTH HORMONE and INTERFERON from a human cell into a bacterium. Segments of DNA for insertion can be prepared by breaking long chains into smaller pieces by the use of restriction enzymes. The segments are then inserted into the aﬀecting organism by using PLASMIDS and bacteriophages (see BACTERIOPHAGE). Plasmids are small packets of DNA that are found within bacteria and can be passed from one bacterium to another.
Already genetic engineering is contributing to easing the problems of diagnosis. DNA analysis and production of MONOCLONAL ANTIBODIES are other applications of genetic engineering. Genetic engineering has signiﬁcantly contributed to horticulture and agriculture with certain characteristics of one organism or variant of a species being transfected (a method of gene transfer) into another. This has given rise to higher-yield crops and to alteration in colouring and size in produce. Genetic engineering is also contributing to our knowledge of how human genes function, as these can be transfected into mice and other animals which can then act as models for genetic therapy. Studying the eﬀects of inherited mutations derived from human DNA in these animal models is thus a very important and much faster way of learning about human disease.
Genetic engineering is a scientiﬁc procedure that could have profound implications for the human race. Manipulating heredity would be an unwelcome activity under the control of maverick scientists, politicians or others in positions of power.