Science Buddies: "Ask an Expert"

I recently just submitted another question(which has already been answered, thank you) but then my mom got me thinking. My project is Forensic Science: Building Your Own Tool For Identifying DNA. I know how the whole Gel Electrophoresis thing works, but can I use a solid small object to travel through the agarose gel? I have some small samples from an old science kit. I thought I could only use liquid. I was just going to use the food coloring dye to act as DNA, RNA, and protein, but my mom is stuck on the whole using real DNA. O_O. So, please answer this as soon as possible and Thank You For Your Time!!!!!!!!!

Your question is best answered by one of our experts from a life sciences field. That does not happen to be me. My personal background is mechanical engineering. But I can read instructions pretty well.

I looked up the description of the project you are working on in the Science Buddies project ideas data base. In the third paragraph under "Introduction", I found this bit of information: "So how does gel electrophoresis work? It is based on the principal that nucleic acids, like DNA and RNA, are negatively charged."

So, unless your food coloring dye contains negative charges like a nucleic acid, it won't migrate through the electrophoresis apparatus. Electorphoresis works on the principle of electric charges applying forces to the mass of the DNA material.

I know this will hurt to hear, but your Mom is right. You need to use DNA/RNA, or some other protein molecule which contains a charge.

Ed Neu
Buffalo, MN

Hi,

Ok, I would just like to add on to Ed's post.

It seems that you need to do a bit more research on gel electrophoresis.

Here's a brilliant site where they take you step by step into learning what this process really is:

http://learn.genetics.utah.edu/content/labs/gel/

As Ed commented, regular food coloring dye, if not charged, probably won't move through the agarose gel because it will not be attracted to the charge. Remember the gel is molecular, and since your "small solid objects" probably are not charged, they won't move efficiently through the gel. Also, the point of electrophoresis is to separate different size DNA molecules. This doesn't really work with a solid object because it won't break apart whereas DNA molecules are dissolved in a liquid.

Here's a project where they use charged gel to simulate DNA's movement.

http://biotech.biology.arizona.edu/labs ... _teac.html

I don't know if you can actually carry out this specific project, but it should help you understand the purpose of using dye.

I don't know what your resources are, so I'm not sure if you can use actual DNA. That in fact, will be much more complicated and there are various safety issues that arise.

Hope this helps,

Manjinder

Thanks so much. When i asked a question befre i kind of got confused so this will hep alot. Those web sties look very helpful and I will look at them right after writing this! Thanks Both!!