Methods:
We took 5 samples of DNA and used three separate restriction enzymes to cut it. Each sample of DNA contained a combination of restriction enzymes, and then was placed into separate wells on the electrophoresis gel. This is what each sample of DNA contained:
1. Marker (Only contained DNA)
2. DNA + PstI
3. DNA + PstI/HpaI
4. DNA + PstI/SspI
5. DNA + PstI/HpaI/SspI
Once each sample was placed into the gel wells, the entire gel box was placed into the gel electrophoresis machine. Electricity is run through the gel, propelling the light (smaller) strands a DNA far away from it's original position, and propelling heavy (bigger) strands of DNA a smaller distance from it's original position. We then tallied the size of each strand of DNA based on it's distance from the origin, and also by comparing the DNA strands to the marker in well 1.
Discussion:
By observing the positions of the strands in each well in relation to the marker, we were able to approximate the length of each strand. When all of the strand lengths added up to 2,600 base pairs in well two, we then knew that wells three, four, and five must also have the same number of base pairs. We were able to create restriction maps containing each restriction enzyme according to the length of DNA strands and number of base pairs in each strand. For example, well two contained two fragments of 900 and 4700 base pairs. so therefore there must have been two restriction sites, creating two sections of DNA made of 900 and 4700 base pairs. We were able to perform the same action on well three and four, creating restriction maps for each of their restriction enzymes, respectively. In order to make a restriction map of DNA cut by all three enzymes, we simply superimposed each map from well two, three, and four on top of eachother.
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| Here is an image of the number of base pairs per DNA strand |
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| Here are our restriction maps for each enzyme |
