Basic DNA Extraction Protocol

December 5, 2015 | F.Lab Instructables features a basic DNA extraction protocol titled 5 Minute DNA Extraction in a Shot Glass (by user macowell). It claims to create a drinkable shot that contains your own DNA extracted from your saliva. It is highly recommended that you do not drink such a shot containing dish soap, but it is still a quick way to extract and see DNA.

We also employed a few tips from this online video courtesy of Cold Spring Harbor's DNA Learning Center. If you've never tried anything like this before or would like to know more about DNA barcoding, this is an excellent video.

We've been using this with a slight modification. Instead of using over-proof rum, we used rubbing alcohol but because of this, now you really can NOT consume the DNA! 

Introduction 

This DNA extraction protocol is mainly for demonstrative purposes only. It allows you to extract and visualize the DNA from an organism of choice. You can practice methods of moving liquids and get a feel for what sort of equipment you might want in the future to do this.

Despite the Instructable it is based on featuring a 'drinkable shot,' under no circumstances should you consume the results of this protocol! Rubbing alcohol is poisonous and dangerous if consumed.

Materials + Equipment 

Centrifuge (optional/see here)
Shot glass or glass container of similar size
Table salt
Dish soap (containing sodium laurel sulfate in its ingredients)
Ice cold rubbing alcohol (70%-90% isopropanol will not freeze if you put it in your typical home freezer -- but please make sure it is clearly labeled)
Straw (ad hoc pipette)

Step 1

Your sample needs to be in liquid form. It is essential that if you are examining a plant or other solid biological sample (sample sizes should be no larger than the size of a pencil eraser) that the cells be sufficiently broken up to release the DNA within. Our rice sample needed to be crushed with a pestle. Distilled water (or if it is just for illustrative purposes, any source of water) must be added to just cover the sample.

Step 2

Add 2-3 drops of dish soap

Step 3

Add a "pinch" of table salt.

Step 4

Add a thin layer of rubbing alcohol (3-4 drops) to the surface.

In this step you should see the DNA. It will appear white and cloudy.

Step 5 (optional)

Draw off the supernatant (the top layer of liquid above any solid material you may have) into a separate container. The extracted DNA will be included in this liquid and depending on how well your extraction went you may have quite a bit in there.

Step 6 (optional) 

Spin down the supernatant using a 1.5 mL microcentrifuge tube (with snap cap). You can spin it on high for about 1 minute. When done, you should see a highly concentrated "pellet" at the bottom of an otherwise clear liquid. That is the DNA.

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