Science Buddies: "Ask an Expert"

For my science fair project, i am building the gel electrophoresis chamber with the dyes. The chamber was working with dyes in every other well, and the bands started to form, but when I checked on it, the middle dye had spread all throughout the buffer solution causing it to turn yellow. do you know what could have caused this?

Hi, there are a few things that could have caused the dye to spread into the buffer. Depending on how long you ran the gel, it could have run through the gel and into the buffer. In this case, you would want to run the gel for a shorter amount of time. Another possibility is that the dye wasn't added far enough into the well. A third possibility is that the bottom of the well was punctured, and the dye escaped through the hole. I hope this helps!

I am making the gel electrophoresis chamber, but when I injected blue dye into the well, it expanded and there was blue dye around and possibly under the gel. Will it still work?

It might still work. Occasionally a small amount of dye might escape the well when you remove the dropper. However, it shouldn't be more than a very small amount. Some things that will help keep the dye in the well are using a dropper with a thinner tip, adding the dye very slowly to the well, and making sure there aren't any air bubbles in the dropper when you inject the dye. If you inject air into the well, it usually pushes the dye out.

Hi, after I completed my experiment, I was wondering how to read the results, and how to tell which dye color had the most DNA. What do the results mean?

lily123 wrote:Hi, after I completed my experiment, I was wondering how to read the results, and how to tell which dye color had the most DNA. What do the results mean?

Hi Lily,

The purpose of this experiment is to learn how gel electrophoresis works to separate macromolecules by size. Though this technique is used to analyze DNA, you didn't actually test DNA in your experiment, you used food coloring since it's easier to work with. You probably saw that some of the different food colorings you tested are made up of a few individual colors. For example, green is actually a blue dye mixed with a yellow dye. Running these through the gel let you separate them because each dye is a different size.

The background page for the experiment has a lot of helpful info and a nice video demonstration that includes a bit of explanation. Check it out!

Does that help at all? Let us know if you have more questions!
Megan