For each gel picture, make a figure caption and legend, so you can refer to them in the text. The order of the lanes is the same as the examples in lab, and as given in the manual. (A key is provided below for reference.)
First, briefly describe the appearance of the gel. Where do you see bands? What size are they? Are they bright or faint? (e.g. “Lane 2, the known male, shows a bright band of about 750 bp…”)
For the discussion, you should analyze each gel picture they way we did in lab. What conclusions can you draw from the gel? How confident are you about these conclusions?
In addition to the main goal of this experiment (what was it?), this experiment is intended to get you thinking critically about experimental control and troubleshooting. In order to reach any conclusion based on a gel, you have to look at all the controls that were part of this experiment. Each part of the experiment had controls, which allow you to narrow down where possible error had occurred. Before you dive into analyzing the gel pictures, discuss what each of these controls was and how you can use them to tell whether each part of the experiment worked as expected or not. Where (which lanes and what size) would you expect to see amplified bands on a gel if everything worked as expected?
Specifically, your discussion should address the following: How can you tell whether the DNA extraction worked? Which controls were in place for this step? How can you tell whether the PCR worked as expected? Which controls were used for this step? How can you tell whether the gel electrophoresis worked well? What were the controls for this step? As you address each gel picture, discuss your interpretation of the controls.
Finally, address any specific issues that came up in your group’s experiment (remember you had to take careful notes during the experiments) and how it might have affected the results. For example: Did any of your samples look different or not as expected during weeks 1 and 2? Did you run out of any of the reagents? Did you have to redo anything? Were pipetting errors involved? Don’t just list mistakes, but rather, think about and discuss the possible effects of each.
Give a brief concluding statement. What does this lab demonstrate overall?