Electrophoresis and DNA fingerprinting
Jani Lynette Hagen
October 31,2014
U74644799
Electrophoresis is a technique which uses an electric field to separate molecules, allowing for identification and characterization of the molecules. It is commonly used to separate nucleic acids and protein molecules of various sizes. To prepare the gel for electrophoresis the amount of agrose needed must be calculated. For a 0.8 percent gel 0.8 grams of agrose is necessary per 100 ml of buffer. The DNA fingerprinting experiment only called for 50ml of buffer, therefore only 0.4 grams of argose was needed. Once the buffer and argose were combined, the solution was microwaved until the argose had completely dissolved. While waiting for the solution to cool, the gel box was assembled by putting the gel tray into it and placing the gel comb at the end of the tray. As soon as the argose solution was cool enough to handle, our TA added ethium bromibe to our solution. Ethium bromide is useful as a fluorescent tag (nucleic acid stain) for electrophoresis it binds to DNA and when exposed to UV light it glows bright orange. After the ethium bromide and the agrose gel were combined, the new mixture was poured into the gel tray and allowed to solidify. Once the gel became solid, it was carefully removed along with its tray from the gel box. Next, it was repositioned it so that the wells were on the negative side of the box. Since, DNA fragments are negative; this caused them to migrate away from the negative electrode. The electrophoresis device was then filled with 250ml of the 1X TBE buffer. The surface of the gel should be completely submerged. Finally, we removed the gel comb and added the sample. Thirty micro meters of each sample was placed in the wells according to the following order:
Lane
Tube
Description
1
Markers
Standard DNA Fragments
2
CS1
DNA from crime scene cut with enzyme 1
3
CS2
DNA from crime scene cut with enzyme 2
4
1
DNA from suspect 1 cut with enzyme 1
Cited: (2014, Oct. 14 ). In Electrophoresis. Retrieved Oct. 31, 2014, from http://en.wikipedia.org/wiki/Electrophoresis (Year, Month. Day ). In Lab 6B - DNA Fingerprinting. Retrieved Month. Day, Year, from http://www.biologyjunction.com/sample_6b_dna_lab_ap.htm Nakate, Shashank.. (2011, Jun. 20 ). In Electrophoresis Uses. Retrieved Oct. 31, 2014, from http://www.buzzle.com/articles/electrophoresis-uses.html