Extracting DNA from plant or animal sources is a fairly straightforward procedure, and can even be done at home. However, to our knowledge, no one had previously created a DNA extraction protocol that also functions as a cocktail recipe. The DNAquiri is an attempt to fill this scientific void. The cocktail consists of a strawberry puree layer and an alcohol layer, where the DNA from the strawberries is extracted into the alcohol layer. Because DNA is an extremely long polymer, when it clumps together in the alcohol layer it forms long strands that are visible to the naked eye and can be picked up with a toothpick.
This is a project that was developed and presented (and won Best In Show!) at Science Hack Day San Francisco 2011. http://sf.sciencehackday.com/
Step 1: Gather supplies
ice cold Bacardi 151
frozen sliced strawberries
frozen pineapple juice concentrate
Scale or measuring cups
Narrow glasses for serving
This ingredient list differs significantly from the materials for a standard home DNA extraction. Key changes:
-Normally, surfactants such as dish soap are used to lyse cells. These are not very tasty. Instead, we start with frozen strawberries, in which most cells have already been lysed by the freeze/thaw process. We found that no surfactant was necessary when starting with frozen fruit. Strawberries also gave us the most DNA by far, probably because commercial strawberry strains tend to be octoploid, i.e. they have 8 copies of DNA per cell. (See also How To Extract DNA From A Strawberry.)
-Salt is usually added to enhance precipitation of the DNA. We found salt unnecessary and were able to obtain reasonable yields while omitting it.
-Meat tenderizer is often added to help break down proteins and free the DNA; this mimics the effect of proteases that would be used in a lab setting. Instead, we used pineapple juice, which contains the protease bromelain. (Note that canned pineapple should not be used, since the heat used during the canning process deactivates bromelain.)
-High-proof alcohol (greater than 80 proof) is required for DNA precipitation. Since a daiquiri would traditionally be made with rum, we selected Bacardi 151. (Cheapskates can use Everclear - both are 151 proof, or 75%.)