Science Buddies: "Ask an Expert"

What do eacg of the ingredients do in the DO IT YOURSELF DNA?
Salt, Alcohol and Dawn

Hi, this is a new topic for me, so I started by looking up the words, "lyse" and "octoploid."

But that didn't help me answer the question about what the salt, detergent, and alcohol do in the experiment. Then I noticed the Introduction describing the experiment, and I found this paragraph:

How do scientists get the DNA out of a cell so that they can study it? This is called a DNA extraction, and there are many DNA extraction kits available from biotechnology companies for scientists to use in the lab. During a DNA extraction, a detergent will cause the cell to pop open, or lyse, so that the DNA is released into solution. Then the DNA can be precipitated out of the solution by adding alcohol. In this experiment you will make your own DNA extraction kit from household materials and use it to purify DNA from strawberries.

So the detergent salt-water solution causes the cells to pop open (i.e., lyse). The alcohol causes the DNA to precipitate out of the solution. (Look this up if you're not sure what "precipitate" means.)

The link at the bottom of the procedure brings up a related experiment that calls the salt-water & detergent a "DNA extraction buffer." I looked that up on Google and found this page http://www.eeob.iastate.edu/faculty/Wen ... action.htm It says that the detergent breaks up the membranes of the cells, so they release their contents. It says also that a high-salt solution separates DNA from proteins.

This is a very interesting experiment. I never would have thought it was possible to extract DNA at home!

Please feel free to ask more questions if the explanation I've given is not clear enough.

Bill