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The Science Behind the Embark Dog Age Test


Three Golden Retriever dogs at different ages pictured on a teal background.

As of October 4, 2022, the Embark Dog Age Test is available to order. The Age Test uses a dog’s DNA to measure their calendar age. Specifically, it uses a type of DNA marker called methylation.

Here, we explore the science behind the Age Test and explain how DNA methylation can be used to calculate a dog’s estimated age with remarkable accuracy.


DNA allows us to measure dog age

There are several physical clues that veterinarians use to estimate dog age, including body shape and lens clarity. Teeth can also indicate a dog’s age, although not all dogs follow the same progression from puppy teeth to adult teeth, and age is harder to determine after puppyhood.

Even trained experts sometimes get age identification wrong when judging by visual cues alone. That’s why we use the scientific field of epigenetics to estimate your dog’s age, based on DNA markers.

“Studies have shown age determination based on physical exam findings in adult dogs (including eye clarity, dental tartar, and tooth wear) does not yield a highly accurate result, despite pet care professionals’ best efforts with available parameters. DNA methylation offers a new method for estimating age that is much more precise. Additionally, this exciting technology may help pave the way for future discovery in dogs.”

— Jenna Dockweiler, MS, DVM, DACT, CCRT, CVAT, Veterinary Geneticist at Embark

Genetics vs. epigenetics

If you’ve used a dog DNA test, you’re probably familiar with genetics—the study of DNA. Epigenetics is a related field that looks at factors that interact with DNA.

According to the Centers for Disease Control and Prevention

“Epigenetics is the study of how your behaviors and environment can cause changes that affect the way your genes work. Unlike genetic changes, epigenetic changes are reversible and do not change your DNA sequence, but they can change how your body reads a DNA sequence.”

Epigenetic marks influence how the genes coded in the DNA are expressed. From early on in development, they tell the cells in our bodies what type of cell to become. Epigenetics can change with environment, lifestyle, stress, disease, or age.

There are many kinds of epigenetic marks that can affect DNA. The Embark Age Test uses one type of epigenetic mark, called DNA methylation, which tells us about a dog’s age. 

What is DNA methylation?

DNA methylation is a type of epigenetic modification. It doesn’t change the DNA, but it can affect which genes are turned on and off, and when. 

Methylation refers to a methyl group (one carbon atom and three hydrogen atoms, or CH3) that can be attached to a DNA strand. Our DNA is made up of four letters—A, C, T, and G. Most methylation occurs on letter C, although A can also be methylated. (Learn more about these four letters and how DNA works.)

In the diagram below, the yellow marks represent methyl groups that attach to the sides of the DNA strand. These methylation sites are not permanently attached. They can be added or removed over time.

Teal background with white lines representing a DNA strand, with yellow marks representing methylation on the sides of the DNA.

Methylation is a normal process that happens in your cells (and your dog’s cells). It acts as a stop sign, telling genes when to turn on and when to turn off. Even though these methyl groups are tiny molecules, they are large enough to physically block proteins from accessing the DNA. If there is a high level of methylation, then it becomes harder for proteins to “read” the DNA, so that gene is turned “off.” If the methylation is removed, the DNA becomes open and accessible, so that gene can turn back “on” again.

To learn more about epigenetics and DNA methylation, watch this video: 

The study of DNA methylation is an established science

Research on epigenetics and aging has been ongoing for decades. In the past 10 years, scientists have been able to use DNA methylation to estimate age. There are published papers showing this method works in dogs, humans, and many mammals.

DNA methylation is one of the most well understood epigenetic mechanisms that regulates gene expression in a cell (Arneson et al. 2022). Methylation doesn’t change the actual genetic code, but it changes how that code is expressed.

Methylation acts as a clock. As we age, the level of DNA methylation changes in a predictable way. Overall, the genome gets less methylated with age, although there are some sites where methylation increases (Field 2018; Horvath 2013). We can use the amount and position of DNA methylation to pinpoint just how old your dog is (Horvath et al. 2021).

How Embark uses DNA methylation to calculate dog age

The Embark Dog Age Test is not a genetic test; it’s an epigenetic test. Instead of looking at the genetic code (which all of our dog DNA tests do), the Age Test measures the amount of methylation in your dog’s DNA and translates it to their calendar age.

“We were determined to create an Age Test that would work on any dog, no matter their background, breed, or size. That’s why we collected information on DNA methylation across the genome for a comprehensive panel of dogs, then trained a rigorous statistical model to convert all that information to age. I used this test on my own rescue dog, Saki, and knowing Saki’s age is helping us work with our vet to improve her care as she ages.”

—Erin Wissink, PhD, Research Scientist II at Embark

How does the Embark Age Test work?

While the Age Test uses the same kind of microarray technology as the other Embark dog DNA tests, it involves a special processing step during DNA extraction. That extra step means that we can’t use the same DNA across our genetic tests (Breed + Health, Breed ID, and Purebred Kit) and the Age Test. These tests are run separately. Each test requires its own swab.

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How accurate is the Embark Age Test?

We designed an algorithm that focuses on the methylation patterns that are very strongly correlated with actual age. To develop our accurate algorithm, we chose 500+ dogs with known ages. These dogs represent:

  • 100+ breeds
  • 200+ mixed-breed dogs
  • Toy, small, medium, large, and giant dogs

A chart showing dogs ranging in age from 6 months to 18 years, and ranging in size from 5 lbs to 140 lbs.

We then measured the amount of DNA methylation across the dogs’ genomes.

A conceptual diagram showing dogs of three different ages and the amount of methylation in their DNA over time.

We used that information to create an algorithm for the Age Test that allows us to estimate most dogs’ ages within 5 months in either direction of their true calendar age. 

A bell curve graph showing that Oliver's estimated calendar age is 7 years, 2 months old.

An example of how confidence levels may appear in Age Test results.

After extensive testing with hundreds of dogs who ranged in age from four months to 18 years old, from over 100 breeds and breed mixes, and of various body sizes and weights, our science team is confident we have developed the most accurate canine age test on the market. For details, you can read more about how we validated the accuracy of the Age Test.

Why Age Test results might not be what you expect

As we’ve discussed, a dog’s age can be hard to estimate from visual clues alone, despite our best efforts. Using a methylation test often gives a more accurate age estimate, but it also means that the results can be surprising.

While many factors contribute to your dog’s DNA methylation across the genome, including size and sex, we have accounted for these factors when developing the Age Test. We included dogs with different life histories and home environments in our reference panel to alleviate the impact of these factors on our results. However, it is possible that nutrition and/or stress may affect our methylation results. Based on our rigorous research and reference panel of 500+ dogs, we’re confident in the accuracy of our Age Test.

We understand that it can be hard to find out that your dog’s calendar age is older than you thought. The good news is that having an accurate estimate of your dog’s age can equip you with the information needed to make informed decisions about their care.

How a dog’s age can impact care

Did you know that proactive care plans can change as your dog ages? With your Embark Dog Age Test results, you’ll also get access to helpful care information based on your dog’s life stage as they mature from puppy to adult to senior.

In fact, 40% of Embark customers who used the Age Test made a change to their dog’s care after receiving their results. These changes included scheduling an appointment with their veterinarian, changing their dog’s exercise routine, or supplementing their dog’s diet, among others.

Learn more about dog life stages and health considerations to keep in mind as your dog celebrates more birthdays.

How to order the Embark Age Test

The Embark Age Test is available to order online. You’ll receive an at-home collection kit, including a swab and a return envelope. Simply swab your dog’s mouth following the instructions and mail the swab back to us.

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Mimi Padmabandu Contributor

Mimi Padmabandu is a scientific writer and Senior Content Strategist at Embark Veterinary. Her career includes a decade of experience writing about science and genomics for leading biotechnology companies, including Illumina, Thermo Fisher Scientific, and more. She holds a bachelor's degree in Molecular, Cell, and Developmental Biology from UCLA and a master’s degree in Early Modern English Literature from King’s College London.

Read more about Mimi Padmabandu

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