DNA Extraction the easy way!

First I would like to apologize for a late posting. The “How Proteins Work in Our Bodies” exercise is, well it is not working so well… maybe next month.

Back to DNA! DNA (DeoxyriboNucleic Acid) is the chemical in our bodies that describes how we look, if we’re a monkey, a fruit fly or a little kid. DNA also serves as a chemical messenger to tell cells how to create proteins. Proteins are the building blocks of our bodies. It is found in every living thing inside of every cell, and even in viruses. Scientists use DNA to discover new medicines, to study our genealogies (ancestors), grow better foods, and even investigate crimes! But it’s inside of our cells protected in another smaller structure called the cell nucleus, so how do we get the DNA out so that it can be studied.

Here’s how:

Materials:
Small clear bowls (I used test tubes because the are easy to show)
A fork or spoon to stir
Measuring spoons
Dropper or straw












Ingredients:
1 egg
Meat tenderizer such as Adolph’s® or pineapple juice
Isopropyl alcohol 75% or purer
Liquid dish soap
1/8 tsp Salt
2 Tbsp water











First we must separate the yolk (where the egg cell is)
from the whites. Crack the egg into a small bowl. Gently lift the yolk out of the whites, letting and extra drip off. Place the yolk in another bowl, or just dump the whites out and return the yolk to the original bowl. Wash your hands, raw eggs can be harmful! Mix the yolk with about 2 Tbsp water and 1/8 tsp salt till it is smooth. Note how cloudy it is. That is mainly fats suspended in the yolk and water.



Add about 1 Tbsp dish soap mix lightly and let stand for 5 minutes. Notice how quickly the mixture clears. The soap is reacting with the fats and water, just like when we wash our hands or clean the dishes!















Using a dropper or a straw, fill three bowls, each
with a small amount of your yolk mixture. A
narrow bowl or a deep tall will work best, because the DNA will float on top of the yolks in the end. Now add just a pinch of the tenderizer to each dish and stir just a little to mix in the powder.

Using your dropper or straw, add the isopropyl alcohol to each dish. Drip it down the side of the dish so it floats on top of the yolk mixture. You should see white stringy stuff floating up into the alcohol. If you use the end of a bamboo skewer or a cotton swab you can gently remove the DNA from the solution.














Now let’s take a look at what happened!

First we removed the fats from the cell using simple soap. Soap is a molecule that at one end attracts fats and oils and at the other end attracts water. The second step was to add our meat tenderizer. Meat tenderizer contains an enzyme (a special chemical that speeds of reactions). It broke open the cell nucleus to release the DNA. Since the DNA is buoyant in water (it floats) it rose into the clear alcohol layer that also floats on water. If you are careful you can save your DNA in a small jar covered with the alcohol. But be careful, it is sensitive to light and air. It also will break down if you shake it too much.

DNA is neat stuff. Even though it has the chemical codes that make each of us different and us different from trees and cats, it is over 90% the same for all living things. It is the different order of DNA’s chemical parts that help determine what and who we are. These bits of stringy goo are what make us work.


Want to explore more?

Here are some other good sources of DNA to try out:

Spinach leaves
Split peas
Chicken livers

I chose eggs because all of these need to be blended first. Use about ¼ cup of each plus ½ cup of water.

You can also try out different soaps. Does anti-bacterial soap work better than regular soap, what about laundry detergent?

We used meat tenderizer as our source of enzymes. Here are some other sources you can try:
Contact lens cleaner
Juice from a papaya
Pineapple juice

Which enzyme works best?

Come back in a month to see what science we can cook up in the kitchen!