Gel+Electrophoresis

Becky Guess

**Basic Description **
====Gel electrophoresis is a method used in order to separate macromolecules such as DNA and RNA, by size and length, and protein fragments by charge, in order to isolate and analyze them. Once loaded into the gel, the samples are separated by applying an electric field that moves the negatively charged molecules through an agarose matrix towards the positively charged end. Shorter molecules move farther and faster than larger molecules due to their ability to easily move through the gel. ====

Fig. 1. Step by step process of gel electrophoresis [1]

**Purpose of Technique **
====This is usually performed for analytical purposes, and often is used after amplification of DNA via PCR. It can also be used for cloning and DNA sequencing as well [2]. Gel electrophoresis is also used help with criminal proceedings such as finding a match for DNA. A DNA profile is created using this technique, which can further be analyzed to locate the highly variable regions that are unique to individuals [7]. ====


 * Origin and History **

Early concepts of gel electrophoresis used Faraday’s laws of electrolysis. They were able to measure the properties of small ions in aqueous solutions using an electrical field. Tiselius was able to improve on earlier devices of this technique, but in the late 1940’s it became obsolete as gel electrophoresis started to use gel matrix instead of aqueous solution to separate the compounds into distinct and stable bands [3].


 * Current Research **

One research article that employs this technique used 2D gelectrophoresis el electrophoresis to help aid in the study of proteomic analysis of proteins. Proteins are an essential part of organisms, controlling all of the organism’s activities all the way down to the level of DNA. 2D gel is being used to create protein profiles and determine the similarities and differences among them. This technique is becoming ideal because it allows the opportunity to combine 2D gel electrophoresis with other techniques simultaneously [4].

====Another article experiments with using 3D gel electrophoresis to determine its usefulness as compared with 2D gel electrophoresis in studying monoclonal proteins (M-proteins). These researchers specifically worked with highly-sensitive 3D gel electrophoresis in order to try and find more minute anomalies between samples. The purpose of the experiment was to characterize M-proteins and their heterogeneity in patients with multiple myeloma [5]. ====

====The final article uses capillary gel electrophoresis to help in the genotyping of hemophelia A. This technique was used to isolate amplicons because it works conveniently, quickly, and produces a high quality product. CGE was used to help separate and study the F8 gene which contains one of the inversions causing hemophilia. A sample is injected into the subject’s capillaries and separation occurs when the voltage is turned on [6]. ====

**References **
[1] http://www.bio.utexas.edu/faculty/sjasper/bio212/biotech.html [2] Smisek, D. L.; Hoagland, D. A. (1989). "Agarose gel electrophoresis of high molecular weight, synthetic polyelectrolytes". Macromolecules 22 (5): 2270.  [3] Vesterberg, Olof (1989). "History of Electrophoretic Methods", Journal of Chromatography, 480, 3–19. [4] Pomastowski, P., & Buszewski, B. (2014). Two-dimensional gel electrophoresis in the light of new developments. TrAC Trends in Analytical Chemistry, 53, 167-177. <span style="font-family: "Times New Roman",Times,serif; font-size: 120%;">[5] Nakano, K., Tamura, S., Otuka, K., Niizeki, N., Shigemura, M., Shimizu, C.,. . . Matsuno, K. (2013). Development of a highly sensitive three-dimensional gel electrophoresis method for characterization of monoclonal protein heterogeneity. Analytical Biochemistry, 438(2), 117-123. <span style="font-family: "Times New Roman",Times,serif; font-size: 120%;">[6] Pan, T., Chiou, S., Wang, C., & Wu, S. (2014). Separation of intron 22 inversion type 1 and 2 of hemophilia A by modified inverse-shifting polymerase chain reaction and capillary gel electrophoresis. Talanta, 130, 328-335. <span style="font-family: "Times New Roman",Times,serif; font-size: 120%;">[7] http://www.colorado.edu/Outreach/BSI/pdfs/gel_electrophoresis.pdf