Plsed-Field Gel Electrophoresis A Revolutional in Microbial Genetics

Abstract

Gel electrophoresis is a relatively simple but reliable technique for the analysis of DNA and RNA molecules. However, this method, in practical terms, cannot resolve the separatioo of DNA fragments more than 50 kilo base pairs (kbp). Pulsed-Field Gel Electrophoresis (PFGE) was able to overcome this problem by forcing the DNA molecules to change their orientation periodicaily from one electric field configuration to the other. E'FGE anaiysis of large 4zed DNA molecules requires a technique to isolate intact genomic DNA as well as the availability of rare-cutting restriction endonucleases and the appropriate mega-base molecular size markers. Under clptimized condition, PFGE can efficiently separate DNA fragments of 100 to 10,000 kbp to distinguish strains of cnicroorganisms which otherwise exhibit similar or identical physiological and morphological characteristics. This t~echniqueh as also been employed to study the occurrence of genomic rearrangements, plasmid fingerprinting, nautant analysis, cloning, as well as the construction of physical maps. This review is intended to introduce the principles of PFGE and its applications in the genetic analysis of microorganisms.