How to Test Dog Poop DNA

We see DNA testing in almost every TV show, hear about it on the radio and see it online, so how can the average person test dog poop DNA? Is that even possible?

What happens when a neighbor's dog poops on your lawn, how can you test the poop and match it to the dog? Is there a test kit that can be purchased?

Unfortunately DNA testing is a relatively complex process and requires lab equipment and supplies as well as an assay kit which is specifically developed to test genetic markers found only in dogs.

The most common assay kit is the Stockmarks Kit available through Thermo Scientific which provides 10 unique markers to help identify dogs and is most commonly used in parentage testing.

Genotyping or genetic fingerprinting uses the size fragments of portions of the DNA to determine matches. This allows us to determine the parents of a puppy or if the poop on the lawn belongs to that same puppy.

Simplified DNA Testing Of Dog Feces Explained

The fecal testing process starts by extracting the DNA from the source, or in this case the "Dog's Poop". The dog's DNA is contained in the epithelial or skin cells present in the outside layer of the dog poop sample.

There are several ways to get the DNA strands from the cells, but essentially they are exposed to a soap and salt solution which breaks the cells open and allows the DNA to slip out.

Then, filters are used that separate the DNA from the cells and other poop products. The DNA is purified in a series of steps leaving a tiny drop of water with thousands of strands of DNA.

With the pure DNA we need to isolate the markers and create millions of duplicate copies so there is enough DNA to be measured. This is where the Stockmarks assay kit is used and mixed with the pure DNA and run through a controlled series of heating and cooling steps in a thermalcycler forcing the DNA to split in half. Each half then rebuilds to become 2 full strands and the process continues over and over.

This process called amplification or PCR, takes several hours until there are millions of strands of DNA which can be measured.

The amplified DNA is then measured using a DNA analyzer which creates digital data representing the size fragments of each of the markers in the assay kit. The digital data is output into a graph called an electropherogram which can be compared with the electropherograms of other dogs.

Of course, in the case of parentage testing a lab scientist can easily compare the data from the other and father to see if the offspring was the result of the two parents.

However in poop testing the suspect pool is much larger and software is needed to compare all the data and determine possible matches.

Dog Poop Identification APP

Wouldn't it be great if there was a "Dog Poop APP" on iTunes or Google Play that you could downloaded to take a photo of the poop and get an instant match?

Yes, that would be awesome. But until that day comes, companies like Mr Dog Poop are still the best and most cost effective way to find out who did it.

For an average person to set up a lab and acquire the necessary equipment it is cost prohibitive, likely costing up to a million dollars for everything needed. And that is assuming you use a commercially available assay kit like Stockmarks. If you intend to build a business and want to develop your own markers that would require much more time and testing DNA from thousands of dogs to create a working process.

But when Mr Dog Poop can test samples for $35 it does not make much sense to do it yourself. So until the Dog Poop App is invented, the process is still one that requires a sophisticated DNA lab and advanced software to determine which dog pooped on the lawn.