DNA methylation is the most well-known type of epigenetic marker. It’s a chemical modification that doesn’t change the actual genetic code of the DNA, but can change how genes work. Methylation patterns can change with environment, lifestyle, stress, disease, or age.

As your dog ages, the level of DNA methylation changes in a predictable way. We can use the amount and position of DNA methylation as a type of “clock” to estimate age (Horvath et al. 2021).

Studying the relationship between methylation and age is a cutting-edge area of science. There are published papers showing this method works in dogs, humans, and many other mammals.

For more details, read this article explaining the science behind the Age Test.

The Age Test uses a saliva sample collected with a cheek swab, just like our other DNA tests (Breed ID, Breed + Health, and Purebred), but that’s where the similarities end. The Age Test does not provide genetic health results, your dog’s breed breakdown, access to our Relative Finder tool, or ancestry information.

The science of the tests is also very different. Our other DNA tests are based on your dog’s DNA sequence, which was present from birth. The Age Test, on the other hand, relies on epigenetics—the study of how external factors can change the way genes work. The Age Test estimates a dog’s age by using a technology that focuses on DNA methylation patterns.

Because of these differences, the same swab cannot be used for both tests. Each test is run separately and requires its own swab.

In your results, you’ll receive an estimated age and birthdate for your dog, plus information about how to interpret those results.

Your results will also include what we call a prediction interval—the range of dates likely to contain your dog’s true birthday. Their estimated birthday will be within this range. While there’s no way to be sure of the exact day, this is our best estimate, based on their methylation profile.

With the Age Test, 77% of dogs have a true birthday within 12 months of their estimated birthday.

This means that if one dog takes the Age Test multiple times, they may receive different estimated birthdays, but we expect 77% to fall within the same prediction interval in the test results.

Although it does not pinpoint the exact date of your dog’s birth, the Age Test is comparable to the most accurate methylation clock models available today. It also follows scientific best practices for measuring the accuracy of this type of model.

Here are just a few of the steps we took to develop the Age Test and make sure that it meets our standards for accuracy and scientific integrity:

1. We developed a carefully curated reference database of thousands of dogs with known ages, as well as different breeds and mixes. We used this reference set, as well as data from the early-access period of the Age Test, to train our model.
2. We have done rigorous internal and external validation, with help from scientists at Embark as well as other experts in the field, to prove out the efficacy of our model.
3. We added several steps to the model development procedure to ensure that we have created the most accurate model available for methylation technology today.

Learn more about our statistical model in this explainer about the science behind the Age Test.

(Please note that the Age Test was specifically developed for dogs. While there is no species check in our process, the Age Test is meant to be used with canine DNA only.)