Spit, soap, salt, spirits, then see!

Okay, maybe you won't see a colorful double helix, but you WILL see your DNA!

The topic of today’s post is an oldie, but a real goodie. In short, I’m going to describe how you can isolate your own DNA, with stuff you most likely have right now in your kitchen. If you’re wondering, “Why on earth would I want to isolate my DNA?” then you may need to step up your nerdy game. Looking at your own DNA is just so cool, like, “Oh, look, it’s that stuff that encodes everything that I am!” Not only that, your DNA would make a great last-minute economical gift for a significant other (see: Angelina Jolie and ex-husband Billy Bob Thornton having worn vials of each others’ blood). At the very least, you can do this with a kid and get him/her started with nerdy early.

So, if you want to get hold of that stuff that basically makes you who you are, what you’ll need is…

• A shot glass, or other small glass
• A little table salt
• Some dish soap
• Chilled alcohol, at least 120-proof (tip: rubbing alcohol makes things seem more kid-friendly than, say, rum; whatever you choose, the higher the proof, the better)

Simple! Got everything? Okay, first step…

1. Spit. The DNA you’re collecting is going to come from your cheek cells (your DNA is the same in all of your cells, by the way), so there’s no getting around the spitting. A bit gross, maybe. You have two options:

• Work up a lot of spit while thinking of delicious things and simultaneously rubbing your cheeks against your teeth (the more cheek cells, the better); spit into the glass. Repeat this until the glass is about 1/4 full.
• Alternatively, fill the glass 1/4 full with water, add a pinch of salt, and gargle good and well with that (the salt will help rub cheek cells off). Spit it back into the glass.

All set with the spit? Next up…

2. Soap. Add 2-3 drops of the soap to the spit.

You need to break your cells open to get the DNA out, and the dish soap is going to do that because it has detergents that can disrupt cell membranes. A clear version might be ideal for seeing everything really well, but you’ll be fine either way.

Now you’ve got a bunch of broken cells and everything that was inside them, including your DNA, floating around in your glass. But we don’t care about random proteins right now, we want to see DNA, so next we need…

3. Salt. Use your fingers to add 2 or 3 pinches of salt to the glass (err on the side of 2 pinches if you chose the salty spit method in step 1). Stir gently. (Science might be the one setting where bubbles are generally a bad thing.)

DNA is negatively charged, and things with the same charge repel each other. But we want our DNA to clump together so we can see it, and the positively charged part of salt will help the DNA molecules to stop being so negative and get closer together (hahaha).

Okay, you’re almost there! One step away from isolating a universally unique substance! (Unless you were one of a multiple birth of identical babies, then this is multiple times less exciting…. Kidding!) Lastly,

4. Spirits. Take your cold, 120-proof-or-greater alcohol and carefully pour a little down the side of the glass so that it layers on top of what’s already in there. You don’t have to be really exact here (or at any point up to now, I guess), but shoot for 1/3-1/2 the volume of what’s already in the glass.

Alcohol and DNA are something like oil and water, so this step helps the DNA separate out so you can see it (step 5: See it!). And you should be seeing it in 5 minutes or less! It will look like some sort of nasty, stringy, white stuff. You can use a toothpick or a fork to swirl it around, play with it, take it out of the glass and put it into a locket for your soul mate.

And there you have it! It’s incredibly easy, you probably have everything you need already, and it all takes less than 10 minutes. I want to emphasize that I know this procedure is all over the internet in various forms (because there’s no one “right” way to do it, and you can essentially do this with anything that has DNA!), but I think it’s such a great, simple way to try nerdy from the comfort of your own home, so I just had to share it.

I encourage you to pass this one on to anyone who might have the slightest interest in nerdy stuff, because it’s totally accessible even if you have no science background. And I’m all for all-inclusive science!

Hearn, R., & Arblaster, K. (2010). DNA extraction techniques for use in education Biochemistry and Molecular Biology Education, 38 (3), 161-166 DOI: 10.1002/bmb.20351