How to Extract DNA From an Onion
Deoxyribonucleic acid, or DNA, is a large molecule that carries genetic instructions used in the development of all living organisms, including fruits and vegetables. Extracting DNA from an onion is relatively easy because the onion's low starch content allows the DNA to be seen more clearly. Common household items combined with some simple steps are all that are needed to extract the DNA.
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Things You'll Need
- Rubbing alcohol
- 2 clear glasses
- Freezer or bowl of ice
- Yellow onion
- Knife
- Tap water
- 2 cup-size glass measuring cups
- Salt
- Microwave
- Hand blender
- Dishwashing liquid
- Coffee filter
- Rubber band
- Meat tenderizer
- Popsicle sticks or toothpicks
Instructions
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1
Measure 1 cup of rubbing alcohol into a glass. Place it in a freezer or into a bowl of ice. Leave it there while you continue with the rest of your preparations. The alcohol must be chilled in order to extract the DNA from the onion.
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2
Cut a yellow onion in half. Peel one half of the onion. Then cut the half into small pieces. The remaining half is not needed.
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3
Pour 1/4 cup of tap water into a glass measuring cup. Add 1 teaspoon of salt. Stir until the salt is dissolved. Microwave the mixture for 1 minute.
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4
Add the chopped onion to the salt water. Use the hand blender for 3 to 5 seconds, until all the chopped onion is blended.
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5
Add 2 tablespoons of dishwashing liquid to the mixture. Stir gently with the Popsicle stick or toothpick, trying not to create too many bubbles. Stir for five minutes.
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6
Place the coffee filter over a glass. Use the rubber band to secure it in place.
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7
Pour the onion mixture into the filter and let it strain into the glass. This will take about 30 minutes.
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8
Add 1/8 teaspoon of meat tenderizer to the strained mixture in the glass. Stir with a clean toothpick or Popsicle stick for five minutes.
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9
Remove the chilled alcohol from the freezer or the ice bowl. Pour an amount equal to the onion mixture into the glass. Do not stir. DNA will float up through the alcohol to the top of the mixture. You can catch the DNA on a clean toothpick or Popsicle stick and look at it more closely.
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10
When you are done, you can safely throw away all liquids, materials and onion pieces.
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Tips & Warnings
If the DNA doesn't form, it may be because the experiment took too long. Try it again, but do it more quickly. Try gently pressing the onion mixture through the coffee filter with clean fingers. Also, try using a clear dish liquid and distilled water instead of tap water. You can also extract DNA from other items in your kitchen. Kiwi fruit, peas, yeast and wheat germ all work well.
