435 - Crop Physiology Lab Restriction Mapping of Plasmid DNA Todays lab will serve to illustrate a very important technique involved in genetic manipulation of plants, that of restriction mapping. A gene is nothing more than a section of DNA which codes for, or causes the production of a specific protein. Scientists interested in moving genes from plant to plant must first identify the location of that gene.
Restriction mapping is an important tool for doing that.
At the heart of restriction mapping is the use of enzymes called restriction endonucleases. Restriction endonucleases are enzymes which cut DNA into discreet fragments by cleaving only at specific DNA sequences. There are many restriction endonucleases commercially available, each with a unique recognition sequence. These enzymes allow researches to cut DNA into fragments, which makes the search for a particular gene easier. A particular endonuclease will cut a given DNA strand into one to many fragments, depending on the number of recognition sequences in the DNA sample.