How to Extract DNA From a Strawberry

DNA, or deoxyribonucleic acid, is the material that transfers genetic characteristics in humans, animals and almost all other living organisms, including fruits and vegetables. Ripe strawberries are an excellent source for extracting DNA because they are easy to pulverize, which breaks the cells of the strawberries apart.

Things You'll Need

• Rubbing alcohol
• 1/4 cup Measuring cup
• Freezer or ice
• 3 Clear glasses
• Bowl
• Strawberries
• Knife
• Resealable bag
• Fork
• Water
• Salt
• Shampoo or dish liquid
• Spoon
• 1 tsp. Measuring spoon
• Paper coffee filter
• Rubber band
• Toothpick

Instructions

1. Pour 1/4 cup of alcohol into one of the glasses. Place the glass in the freezer or into a bowl of ice to chill. The alcohol must be very cold to extract the DNA.

2. Remove the stems from three strawberries with a knife. Place the strawberries in a Ziploc bag and seal shut. Then use a fork or your fingers to squish the strawberries until they are completely mashed. This should take a few minutes.

3. Put two large pinches of salt into the second glass. Add one cup of tap water. Stir to dissolve the salt. Add two tablespoons of shampoo or dish liquid to the mixture. Stir gently until completely mixed.

4. Open the bag and add about 5 teaspoons of the soapy solution to the mashed fruit. Seal up the bag and mix with your fingers for about 60 seconds, trying not to develop too many soap bubbles. The detergent mixture opens the strawberry cells, releasing the DNA.

5. Place the coffee filter over the third glass and secure it with a rubber band. Pour the mixture into the filter. If the mixture is too thick to flow through, stir in a little more of the soap solution. Let the mixture filter through. This should take about 10 minutes.

6. Take the filter off and add the ice cold alcohol to the mixture in the glass. After about 5 minutes, you should see a clumpy white substance beginning to form. This is the DNA. The alcohol allows the DNA to float. Use the toothpick or the craft stick to pick up the DNA so you can look at its strands more closely.

7. When you are done, it is safe to pour all leftover liquids and substances down the sink. Throw all trash into the garbage.

Tips & Warnings

• Frozen strawberries can be used, but you must thaw them first. Use a Ziploc bag rather than a sandwich bag because the Ziploc is thicker and less likely to tear. Use a shampoo that is not combined with a conditioner.

References

• Online Dictionary
• University of Washington, Department of Genome Sciences