Extracting DNA from a banana may sound like a difficult task, but it is not very difficult at all. The process involves a few general steps which include mashing, filtration, precipitation, and extraction. Mashing exposes a greater surface area from which to extract the DNA. Substances are also added that will help break-down cell membranes to release the DNA. The filtration step allows for the collection of the DNA and other cellular substances. The precipitation step allows the DNA to separate from other cellular substances. Finally, the DNA is removed from the solution.
Time Required: 20 minutes
- Using your knife, cut your banana into tiny pieces to expose more of the cells.
- Place your banana pieces in the blender, add a teaspoon of salt and slightly cover the mixture with warm water. The salt will help the DNA stay together during the mashing process.
- Mix in the blender for 5 to 10 seconds making sure the mixture is not too runny.
- Pour the mixture into the glass jar through the strainer. You want the jar to be about half full.
- Add about 2 teaspoons of liquid soap and gently stir the mixture. You should try not to create bubbles when stirring. The soap helps to break-down cell membranes to release the DNA.
- Carefully pour very cold rubbing alcohol down the side of the glass stopping near the top.
- Wait for 5 minutes to allow the DNA to separate from the solution.
- Use the toothpicks to extract the DNA that floats to the surface. It will be long and stringy.
- When pouring the alcohol, make sure that two separate layers are being formed (The bottom layer being the banana mixture and the top layer being the alcohol).
- When extracting the DNA, twist the toothpick slowly. Be sure to only remove the DNA from the top layer.
- Try repeating this experiment again using other foods such as an onion or chicken liver.
What You Need
- Warm water
- Liquid soap
- Glass jar
- Rubbing alcohol