The objective of this project is to develop a DNA sequencing instrument utilizing the pyrophosphate-based method of DNA sequencing. This is a new method that does not use electrophoresis, radioactivity, or fluorescence. The method works by measuring a pyrophosphate generated by the DNA polymerization reaction. The pyrophosphate is measured continuously by a device consisting of a series of columns containing enzymes covalently attached to a solid support. Phase I will be devoted to solving the remaining biochemical problems associated with the method. If the method is demonstrated to work well enough, phase II will consist of construction of a prototype instrument suitable for large scale production.