Pulsed-field gel electrophoresis

Pulsed -field gel electrophoresis ( PFGE ), or only pulsed field electrophoresis is a method for determining the length of DNA fragments of chromosomal size, for example for determining the genetic fingerprint or for typing bacterial genomes, and thus for the identification of pathogens.

Principle

The difference from a normal agarose gel electrophoresis is that no time- homogeneous field is applied, but is periodically reversed for a short time. In normal gel electrophoresis large DNA strands (about 30-50 kbp ) migrate about the same speed, regardless of size or chain length. By reversing the resolution in this area can be greatly improved. The theoretical foundations are not explored exactly, however, makes this method to own the greater " inertia " of the larger pieces, which can adapt to the changing field slowly and realign. " Snag " The various strands in the struts of the gel, due to the short Umpolphasen dissolve the shorter strands, for the longer is not enough time. So on average to speed relatively shorter in comparison to the longer strands. In the short pieces, the method has no advantages to agarose gel electrophoresis or capillary electrophoresis.