How do we extract DNA from your dogs swab?

PUBLISHED ON June 2, 2017 by michele koltookian

Ever wonder what the process of DNA extraction actually entails, or how your dog’s swab gets transformed into the DNA we use for Darwin’s dogs?


Let’s take a journey through the life cycle of my dog Nax’s swab. The journey starts when Brittney scans the barcode of a new kit, linking it to the profile I created for Nax on the Darwin’s dogs website. From there, the swab travels to my house in NH where I fill out the consent form and swab and mail it back to Darwin’s dogs.

Every day around 3 pm, Brittney receives a box of kits that you have completed and returned to us. She opens and scans the barcode of each box this allows me to know that Nax’s sample has arrived back at Darwin’s dogs. From there the swab is placed in a box and transferred to the lab where the extraction process will start.


Once in the lab Nax’s swab is scanned again for record keeping purposes and then placed into a 50-degree water bath for about an hour.


After an hour Nax’s sample is removed from the water bath it’s opened and all the liquid is manually squeezed from the swab; then poured into a small clear 2mL tube a buffer is added and incubated on ice for 10 minutes. This buffer helps to remove all the impurities (things other then Nax’s DNA) incubating it on ice helps all the impurities to clump together.


After the 10-minute ice incubation Nax’s sample is then spun in a centrifuge. This ensures the clump of impurities sticks to the side of the tube. We are then able to transfer the liquid containing Nax’s DNA to a clean 2mL tube.

impuritites pellet

Now that we have this liquid with Nax’s DNA the next step is to add 100% ethanol, which causes the DNA to come out of solution. We let his sample sit for 10 minutes before centrifuging it again so the DNA that is floating in the liquid forms a clump and sticks to the side of the tube.


Nax’s sample then gets cleaned up by adding a diluted 70% ethanol mixture this is to make sure there isn’t any impurities hanging around. Then all the liquid is removed from the tube leaving behind just the DNA pellet stuck to the side. Once the tube has dried we add water to Nax’s sample and let it sit overnight to allow the DNA pellet to dissolve into the water. Once this is done we officially have DNA from Nax!

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