How to read gel electrophoresis results. Gel electrophoresis apparatus – an agarose gel is placed in this buffer-filled box and an electrical field is applied via the power supply to the rear. The negative terminal is at the far end (black wire), so DNA migrates toward the positively charged anode (red wire).
Digital image of 3 plasmid restriction digests run on a 1% w/v agarose gel, 3 volt/cm, stained with ethidium bromide. The DNA size marker is a commercial 1 kbp ladder. The position of the wells and direction of DNA migration is noted.
The image above shows how small DNA fragments will migrate through agarose gel farther than large DNA fragments during electrophoresis. The graph to the right shows the nonlinear, relationship between the size of the DNA fragment and the distance migrated.
Gel Electrophoresis is a process where an electric current is applied to DNA samples creating fragments that can be used for comparison between DNA samples.
1) DNA is extracted.
2) Isolation and amplification of DNA.
3) DNA added to the gel wells.
4) Electric current applied to the gel.
5) DNA bands are separated by size.
6) DNA bands are stained.
Gel electrophoresis is a method for separation and analysis of macromolecules (DNA, RNA and proteins) and their fragments, based on their size and charge. It is used in clinical chemistry to separate proteins by charge and/or size (IEF agarose, essentially size independent) and in biochemistry and molecular biology to separate a mixed population of DNA and RNA fragments by length, to estimate the size of DNA and RNA fragments or to separate proteins by charge.
Tags: How to read gel electrophoresis results, DNA, RNA, Genetics, Gel electrophoresis