Horizontal gel electrophoresis- The electrophoresis in this gel system is performed in a continuous fashion with both electrodes and gel cassette submersed within the buffer. The schematic diagram of a vertical gel electrophoresis apparatus is given in Figure 24.1. The electrophoresis chamber has two platinum electrodes placed on the both ends are connected to the external power supply from a power pack which supplies a direct current or DC voltage. The tank filled with the running buffer and the gel casted is submerged inside the buffer. There are additional accessories needed for casting the agarose gel such as comb (to prepare different well), spacer, gel caster etc.

Figure 24.1: Different components of horizontal gel electrophoresis apparatus.

Buffer and reagent for electrophoresis- The purpose of each reagents used in horizontal gel electrophoresis are as follows-

1. Agarose- polymeric sugar used to prepare horizontal gel for DNA analysis.

2. Ethidium bromide- for staining of the agarose gel to visualize the DNA.

3. Sucrose- For preparation of loading dye for horizontal gel.

4. Tris-HCl- The component of the running buffer.

5. Bromophenol blue- Tracking dye to monitor the progress of the electrophoresis.