Special Request: Looking at Your Own DNA in your Kitchen.
This week, I got a special request. It was to post instructions about how to isolate a sample of one’s own DNA at home. It is not only possible, it is easy. And very fun. And there is no experience more bonding than sitting around with someone for 20 minutes, spitting into a glass. (Seriously.) SO: Start with about 1 tablespoon of your own spit (or someone else’s, or mix them up. Whatever.) Add about 1 tablespoon of water, one drop of dishwashing liquid, and a shake of salt. Mix vigorously, preferably with a plastic utensil. What is happening here? The soap is breaking open the cells that are present in your saliva and the DNA is coming unspooled (like reeling the tape out of a cassette). Wait for 5 minutes, then gently pour 91% isopropyl alcohol down the side of the glass to create a 2 layer effect (this is not difficult). What happens next? Water, which is very happy to be clinging to DNA, is MUCH happier clinging to the alcohol. This “dehydrates” the DNA causing it to tangle up and precipitate in the alcohol layer. The white cottony looking fluff in the alcohol is your DNA. And yes, this is exactly the way we do it in the lab - the chemicals are cleaner, the purity is higher, but the precipitation with alcohol is just the same. Even in the lab I never get tired of watching this happen.