GMU:DIY Biolab “Driver’s License”/Marie Laure Ebel

HUMAN DNA ANALYSIS

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PRACTICING PCR ANALYSIS

Step 1. Extracting DNA from blood and from pork liver meat

Step 2. STR-analysis with pork meat primer

Step 3. Electrophoresis

#First attempt

=> I got no results : either the ladder nor the DNA samples were "growing" as they should (multiple lines). So I decided to test the ladder only to see if there is a problem from the samples themselves or with the preparation (agarose + buffer TAE 50x+ distilled water) => #Second attempt

#Second attempt

=> Same problem : the ladder was growing as one bloc only (see the little drawing). Even during a 2.2 attempt with new SERVA Stain G (which I thought it could be the problem, since the previous tube was quiet old). Then, I noticed that the positive side was turning in blue color and some part of the agarose gel was melting down. So I decided to test if this bleu color is coming from oxidation of the electrodes themselves, or if the ladder was "swimming" on the extra amount of solution (buffer TAE 50x + distilled water) above the agarose to reach the positive side => #Third attempt

#Third attempt

=> Still turning bleu. Even with smaller electrodes that are completely covered by the solution (buffer TAE 50x + distilled water) So I decided to test if this oxidation is coming from the buffer or if it is simply a natural process => #Fourth attempt

#Fourth attempt

=> First picture : distilled water only. Second picture : distilled water + buffer TAE 50x. No changes at all. So it might come from the SERVA Stain G (which is yellow-ish) or it is actually not a problem and does not affect on the electrophoresis itself.