DNA extract

Introduction to DNA Isolation from Strawberries

• Presenters: Dr. Eric Green and Dr. Carla Easter
  • Dr. Green: Director of the National Human Genome Research Institute
  • Dr. Easter: Education Specialist at the National Human Genome Research Institute
• Purpose: To show how to isolate DNA from strawberries using household items.

Why Use Strawberries for DNA Isolation?

• Attributes of Strawberries:
  • Pleasant smell and visual appeal
  • Edible fruit with seeds on the outside
• Ease of Extraction: Strawberries are a suitable choice due to their high DNA content and ease of access, making it simple to demonstrate the DNA extraction process.

Steps for Isolating Strawberry DNA

Step 1: Prepare the Strawberries

• Use frozen strawberries for easier processing due to their softer texture.
• Place strawberries in a plastic bag to crush them and release the DNA stored within the cells.

Step 2: Create the Lysis Solution

• Lysis: To break open the strawberry cells.
• Materials Needed:
  • 2 teaspoons of detergent (for breaking up the cell membranes)
  • 1/2 teaspoon of salt (to help stabilize the DNA)
  • 1/2 cup of water
• Mixing: Stir gently to avoid excessive bubbles which can complicate the extraction process.

Step 3: Mixing Strawberries with Lysis Solution

• Combine strawberry puree with the lysis solution and gently mix to avoid excessive bubbles.
• Allow the DNA to go into solution as the cell membranes break open.

Step 4: Filtering the Mixture

• Filtration: Use a regular coffee filter to separate the liquid (containing DNA) from solid strawberry debris.
• Pour the strawberry mixture into the coffee filter slowly to avoid tearing.

Step 5: Precipitate the DNA

• Precipitation: A method to make the dissolved DNA visible.
• Add Rubbing Alcohol: Pour an equal amount of rubbing alcohol into the filtered liquid.
  • Alcohol causes the DNA to precipitate out of the solution, forming a visible layer of DNA.
• Observation: After mixing, a gunky, slimy layer will form at the interface of the two liquids, which consists of the extracted DNA.

Step 6: Collecting the DNA

• Use a popsicle stick to spool the DNA for observation.
• DNA appears as a white, slimy substance, free from red strawberry residue.

Applications of Isolated DNA

• Analysis: The extracted DNA can be analyzed similarly to methods used in forensic testing.
• Medical Relevance: The techniques learned can apply to isolating DNA from various biological samples like blood or cheek cells, with implications for medical diagnosis and treatments.

Storing the Isolated DNA

• Recommended to store the DNA in a sealed container (like a zip-lock bag or small tube) in the refrigerator for longevity.

Conclusion

• Encouragement for Experimentation: Students can replicate the experiment at home by following detailed instructions available on the National Human Genome Research Institute's website.
• Final Note: The process is not only educational but also illustrates the relevance of DNA in health and medicine, encouraging curiosity and understanding of genetics.