1. DNA Extraction from Strawberries

2. Lab Safety and Tips Wear Goggles Important to have clean glassware.
Follow directions CAREFULLY or you will not get good results.

3. I DNA Single molecules of DNA are long and stringy.
Each cell of your body contains six feet of DNA, but it's only one-millionth of an inch wide.

4. Chromosomes
Strands of DNA molecules coated with protein

5. Start with a Strawberry: READ lab background
Easy to pulverize- Why?
Already has enzymes-Which ones?
Large genome (lots of chromosomes)-what is octoploid?

6. Add Detergent Buffer
Detergent/shampoo captures protein and releases DNA

7. Mashing Strawberries in a thick Ziploc bag

8. Careful!!
You don’t want Bubbles!
DNA clings to the bubbles.

9. Salt
The salt in the extraction buffer keeps the DNA molecules together and separates them from the protein.

10. Filtering the mixture will remove cell debris and organelles.

11. Note: slowly pouring down the side of the test tube (to form a layer)
95% Cold Alcohol
Alcohol separates the DNA from the other components of the cell
Note: slowly pouring down the side of the test tube (to form a layer)

12. ETHANOL MUST BE COLD! (to create different densities)

13. The DNA will rise into the alcohol layer and can be ‘spooled’ onto the wooden stick be carefully swirling the stick at the interface of the two layers.

14. DNA will look like snot White Stringy You are viewing
the DNA and protein

15. When DNA extractions are performed, if…
No DNA –you messed up!
DNA appears fluffy – you sheared in the extraction process
DNA appears as thin threads. (You Rock!)

16. Does your DNA look like this?

17. If not…Possible Errors
Impurities could have easily been introduced during any step, which may have altered the outcome.
Disturbing the solution as the DNA precipitated could cause poor results probably due to the strands of DNA (breaking up).
Not allowing enough time for each step.

18. You can stain the chromosomes
A. make a wet mount of a thin smear of the chromosomes

19. Schwarz-Slater DNA Slide AWESOME!

20. B. Place one drop of Methylene Blue stain on one edge of the coverslip, and the flat edge of a piece of paper towel on the other edge of the coverslip. The paper towel will draw the water out from under the coverslip.

21. Protect Your Scope!
Be sure to wipe off the excess stain with a paper towel, so you don’t end up staining the objective lenses.
CAUTION: Methylene Blue will stain your skin and clothes.
Goggles and Aprons are required!