On this day, I learned about the various other methods of DNA seperating other then capillary electrophoresis. Of these several methods that I learned about, I was particularly interested about the method of gel electrophoresis.
Gel electrophoresis is a method that is used to separate and then analyze DNA, RNA, and proteins on the basis of their size and charge. Particularly in the interest of my internship, it is often used to separate a mixed group of DNA and RNA fragments by length and to separate proteins by their charges. This process occurs in an agarose matrix. Agarose is a gelatinous mixture and it has a neutral charge and a lower degree of complexity--thus making it less likely to interact with biomolecules. Gels made from purified agarose have a relatively big pore size, making them useful for separating large molecules like DNA fragments. DNA is overall negatively charged and so when they are placed in a gel, an electric field is created across the very gel and so the negative DNA approaches the positive electrode while moving further away from the negative cathode. Shorter molecules move faster and travel further than the longer ones because they are able to move more easily through the pores of the gel. After the process, one will find that the different sized molecules have created distinct bands on the gel.
This method of DNA separation, however, is not commonly used by mentor as it is limited. For instance, the gel may melt during electrophoresis from the heat caused from passing a current across. In addition, comparing the relative quantity of the various molecules rely on the band darkness of the different spots in the gel. It's method consequently has a substantial degree of error. (That is why experiments are usually run several time to get viable results.)
Hopefully by the week I come back from winter vacation, my real mentor, Yolanda, will be back as well so that I may be able to start testing the various samples of DNA for myself!
<Above is a YouTube link demonstrating a slab gel separation.>
Good information, Christi. You demonstrate a nice understanding of electrophoresis. This should serve you well in the future if you ever use this technology. It is very common, so you are bound to be exposed to it if you continue on in molecular biology.
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