So, gel electrophoresis can be used for many different reasons. Here we have an example that shows how gel electrophoresis can be used. It says, using the gel shown on the right-hand side below, determine which rabbit species are most closely related. We have four potential answer options below. Looking at this gel, notice that there are three different lanes, 1, 2, and 3. Within each lane, we have different species of rabbit: rabbit A species here, rabbit B species here, and rabbit C species in the third and final lane.
In order to determine how closely related the species are, what we need to do is compare the band pattern in each of the lanes. When you do this, you will find that the band pattern of rabbit A is very similar to the band pattern of rabbit C, and they share more DNA bands that are in common than any other combination. You can see that this band here is also the same. Maybe not this one here, but this one and this one—these here are all the same. Thus, there is a lot of similarity, and really the only differences that stand out between rabbit A and rabbit C are the bands that are being circled in these positions. These are the only ones that do not match up with each other vertically on the gel.
Because they have such close similarity in this respect, that means that these are the two rabbit species that are most closely related. Our answer is going to be answer option B here, which states rabbit species number 1 and number 3 are the ones that are most closely related, and that's simply because their band patterns match each other the best. Option B here is, therefore, the correct answer for this example problem. We will be able to get some practice applying these concepts as we move forward in our course. So, I'll see you all in our next video.