Chapter 9

DNA Separation Methods: Slab-Gel and Capillary Electrophoresis

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Gel Electrophoresis System

-

Voltage

Gel

Loading well

+anode cathode

Side view Top view

Gel lanes

DNA bands

Buffer

+

-

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Capillary Electrophoresis SystemLaser

InletBuffer

Capillary filled with polymer solution

5-20 kV- +

OutletBuffer

Sample tray

Detection window

(cathode) (anode)

Data AcquisitionSample tray moves

automatically beneath the cathode end of the capillary to deliver each sample in succession ©2002 Academic Press

DNA Separation by Electrophoresis

General Principle

Larger DNA molecules interact more frequently with the gel and are thus retarded in their migration through the gel

Gel

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DNA Separation Mechanisms

Ogston Sieving Reptation

Small DNA molecules

Long DNA molecules

Gel

©2002 Academic Press