By: Amanda Zheng
What is DNA? Deoxyribonucleic acid. It holds all the genetic information needed to code for your body. We learn about it all through biology class but we only see it as a perfect spiral double helix or wound into neat “X” shaped chromosomes. But did you know you can see DNA with your naked eye? Using materials you probably already have in your house, you can extract the DNA from a strawberry to inspect and even touch!
First, put a strawberry (without green leaves) in a sealed ziplock bag and crush it. This pounding breaks the physical cell walls of the strawberry’s plant cells revealing the nuclei, where the DNA lives.
Next, mix dish detergent, salt, and water in a solution and add some of it to the ziplock bag to smush some more. The soap in the detergent can break down the fatty membranes of the cells (similar to how it washes the oil off your dishes!). By breaking the nuclear membrane, it releases the DNA into the solution. The salt works to stick the DNA molecules together and separate the strands from other cell components such as proteins.
Next, filter the strawberry-dish detergent mixture through a strainer or gauze into a test tube so only liquid remains. This will clear out the large solid strawberry chunks.
Afterward, pour ice-cold ethanol alcohol on top of the strawberry solution carefully to produce two layers. Take a look - the DNA will be sitting between the layer of strawberry juice and alcohol! This is because DNA is insoluble in alcohol so it precipitates into clear, long, thread-like webs. It’s that easy!