Extracting your DNA with kitchen suppliesS

Sometimes you get a hankering to see some DNA. With a few household products, you now can do just that. It won't be good for a CSI-style genetic match, but you can extract strands of DNA from yourself, a strawberry, or any other living thing.

Whether you want to grab some visible DNA from a strawberry, from a piece of liver, or from the inside of your own cheek, all you really need is salt, soap, and rubbing alcohol. What you get won't be the elegant double-helix. It's going to look like the gummy, stringy white stuff that's left over when tear a price sticker off a CD case, but it will be pure DNA, and you will be able to look at it.

First grab some warmish water, a teaspoon of salt, and whatever you want to get DNA from. Most guides recommend a banana or a strawberry, or possibly some frozen vegetables. Whatever it is, mash it and the salt water together, either with a fork or by pouring it into a blender. At the end you should have a slightly chunky mess. Don't completely puree it smooth. When you're done blending, pour it through a strainer into a glass. If you want to extract your own DNA, grab the cup of salt water and gargle for all you're worth. You need to keep it in your mouth for a minute or two before returning it, full of spit and cheek cells, to the glass.

Next grab the liquid soap. You should add just a teaspoon full, and stir the mixture very carefully, using something non-organic as an implement. Don't stir up any bubbles. If you don't have soap, or don't want to use it, grab some powdered meat tenderizer, contact lens cleaning solution, or even pineapple juice. They'll all work.

Now it's time for the alcohol. Use isopropyl alcohol, chilled until it's extremely cold. Pour it very carefully and slowly. You'll need a lot of alcohol. Make sure it forms a thick layer over the mixture underneath. Wait for about two to five minutes. You'll see clumps of white material forming on top of the alcohol, often with long strands hanging off of them. That white stuff is the DNA.

DNA naturally clusters together inside a cell. The soap splits open the cell walls to let the DNA come spilling out. It does the same thing to the cells that it does to bacteria on our hands, breaking them up and killing them. The meat tenderizer and pineapple juice contain enzymes that do the same — to different degrees. DNA has a net negative charge. The salt splits up in the water to form ions that surround the DNA, take away its negative charge, and encourage it to re-clump together. Once that's done, all that's necessary is getting the DNA away from the rest of the organic material. While other organic material might dissolve in alcohol, DNA doesn't. It's also less dense than alcohol, so while the rest of the matter settles beneath the alcohol layer, the DNA comes floating to the top. Voila! There's your DNA.

Via Thinkquest, University of Utah twice.