This experiment is provided by Sue Hinojoza, a teacher at Logan High School in Union City, CA.
Q: What is the best material to extract DNA from?
A: Having tried many, I prefer wheat germ. It is inexpensive, easy to get,
store measure and work with, doesn't smell or gross anyone out or produce
health and safety concerns, and it yields tons of snotty stringy DNA & gunk.
I have a bag that I keep in the freezer. It has lasted three years and
counting. Find a health food store and get the raw kind. I also use cheap
dish detergent (Crystal Octagon) and 90% isopropyl alcohol I get at the
grocery store. Works great every time.
Here's what we do (this is from memory and is "short hand" version):
teaspoon of wheat germ in a test tube (I would have them mass it if getting
ahold of electronic balances wasn't such a problem)
add 10 mL hot water
Add 5 drops of dish soap
Mix and smash with a pointed wooden skewer (the type for kabobs or
yakitori) for 5 minutes
Don't let it get too foamy or bubbly
Pour 7 mL alcohol carefully down the side of the test tube
Pull up and spool the DNA at the water/alcohol interface
I allow about 30 minutes for this to make sure they have plenty of time to
play with the DNA and clean up
Sue Hinojoza
Logan High School
Union City, CA 94587