Tools and Techniques of Genetic Engineering
Genetic engineering utilizes a wide range of methods that physically manipulate DNA for purposes of visualization, sequencing, hybridizing, and identifying specific sequences. The tools of genetic engineering include specialized enzymes, gel electrophoresis, DNA sequencing machines, and gene probes. The polymerase chain reaction (PCR) technique amplifies small bits of DNA into larger quantities for identification by other techniques.

Methods in Recombinant DNA Technology: How to Imitate Nature
Recombinant DNA techniques combine DNA from different sources to produce microorganism ``factories'' which in turn produce hormones, enzymes, and vaccines on an industrial scale. Cloning is the process by which genes are removed from the original host and duplicated for transfer into a cloning host by means of cloning vectors.

Phage, plasmids, and cosmids are types of cloning vectors used to transfer recombinant DNA into a cloning host. Cloning hosts are simple organisms which readily accept recombinant DNA, grow easily, and synthesize large quantities of specific gene product.

Applications of Genetic Engineering
Bioengineered hormones, enzymes, and vaccines are safer and more effective than similar substances derived from animals. Recombinant DNA drugs and vaccines may soon replace antibiotics in treatment and prevention of disease.

Recombinant Organisms: How to Improve on Mother Nature
Transfection is the process by which foreign genes are introduced into organisms. The transfected organism is termed ``transgenic.'' Transgenic microorganisms are genetically designed for medical diagnosis, crop improvement, pest reduction, and bioremediation. Transgenic animals are genetically designed to model genetic therapies, improve meat yield, or synthesize specific biological products.

Genetic Treatments: Introducing DNA into the Body
Gene therapy is the replacement of faulty host genes with functional replacements by use of cloning vectors such as viruses, liposomes, and dendrimers. This type of transfection can be used to treat genetic disorders and acquired disease. Antisense DNA and triplex DNA are used to block expression of undesirable host genes in plants and animals as well as those of intracellular parasites.

Genetic Maps, Fingerprints, and Family Trees
DNA technology has advanced understanding of basic genetic principles that have significant applications in a wide range of disciplines, particularly medicine, evolution, forensics, and anthropology.

The human genome project has not only identified sites of specific human genes but has also clarified the functions of introns, transposons, and other types of ``support'' DNA.