LP36154-0

PFGE

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Description

Manipulating and analyzing DNA are fundamentals in the field of molecular biology. Indeed, separating complex mixtures of DNA into different sized fragments by electrophoresis was a well established technique by the early 1970's.

Typically, DNA was isolated intact and then treated with restriction enzymes to generate pieces small enough to resolve by electrophoresis in agarose or acrylamide. Although this procedure still forms the core of DNA separation and analysis in today's laboratories, the rules of the separation have changed.

In 1984, Schwartz and Cantor described pulsed field gel electrophoresis (PFGE), introducing a new way to separate DNA. In particular, PFGE resolved extremely large DNA for the first time, raising the upper size limit of DNA separation in agarose from 30-50 kb to well over 10 Mb (10,000 kb).

After this initial report, a succession of papers described new and improved instrumentation and methods. As a result, routine procedures and several commercial pulsed field units are currently available. Now, instead of cloning a large number of small fragments of DNA, PFGE permits cloning and analysis of a smaller number of very large pieces of a genome.

Although the theory of pulsed field electrophoresis is a matter of debate, qualitative statements can be made about the movement of DNA in agarose gels during PFGE. During continuous field electrophoresis, DNA above 30-50 kb migrates with the same mobility regardless of size. This is seen in a gel as a single large diffuse band. If, however, the DNA is forced to change direction during electrophoresis, different sized fragments within this diffuse band begin to separate from each other.

With each reorientation of the electric field relative to the gel, smaller sized DNA will begin moving in the new direction more quickly than the larger DNA. Thus, the larger DNA lags behind, providing a separation from the smaller DNA.

Currently, there are three models that attempt to describe the behavior of DNA during PFGE (reviewed by Chu, 1990), the biased reptation model (BRM), the chain model, and, most recently, the bag model (Chu, 1990, 1991).
(<http://www.nal.usda.gov/pgdic/Probe/v2n3/puls.html>) Source: Regenstrief LOINC

Basic Part Properties

Part Name

PFGE

Part Display Name

Pulsed-Field Gel Electrophoresis (PFGE)

Part Type

Method (Describes the method by which the test was performed)

Created On

2005-09-29

Construct for LOINC Short Name

PFGE

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