General Information
Site-directed mutagenesis can be used to change particular base pairs in a piece of DNA. There are a number of methods for achieving this. The approach described here is adapted from the Stratagene site-directed mutagenesis kit, the manual can be found here. Even when using a kit it will be necessary to design primers that are suitable for the specific changes you want to make to your DNA. Most of the contents of the kit can be found in your favorite labs stocks so you may not need to buy the kit itself. If you have problems with this procedure, you can try 'Round-the-horn site-directed mutagenesis which uses PCR to amplify the desired mutant product.