There have been many developments over the past three decades that have led to the efficient manipulation and analysis of nucleic acid and proteins. Many of these have resulted from the isolation and characterization of numerous DNA-manipulating enzymes, such as DNA polymerase, DNA ligase, and reverse transcriptase. However, perhaps the most important was the isolation and application of a number of enzymes that enabled the reproducible digestion of DNA. These enzymes, termedrestriction endonucleasesorrestriction enzymes, provided a turning point for not only the analysis of DNA but also the development of recombinant DNA technology and provided a means for the detection and identification of disease and disease markers.
