An important message about the Age Test
We recently discovered that the Age Test wasn’t performing in a way that met our scientific standards or our commitment to our customers and their dogs. We’ve paused the sale and processing of the Age Test and are dedicating significant resources to resolving this issue.
With recruiting and modeling efforts underway, we’re optimistic that we’ll be able to dive deeper into the scientific challenges of methylation technology and develop the most advanced, high-quality Age Test.
We are committed to ensuring the scientific integrity of the next iteration of the Age Test and have taken several steps to ensure that we continue to provide quality DNA products for you and your dog. Further, this Age Test-specific issue in no way impacts the accuracy of our longstanding DNA products—Breed ID, Breed + Health, and Purebred tests—which are founded in decades-old genotyping technology and use prediction models that our scientists have spent years refining. For more information, please see our full statement detailing next steps for the Age Test.
Here, we explore the science behind the Age Test and how it uses a type of DNA marker called methylation.
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 measure your dog’s age based on their DNA.
“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. (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.
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 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:
What do scientists know about DNA methylation?
Research on epigenetics has been going on for decades, and scientists have studied DNA methylation specifically for much of that time. In fact, 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.
More recently, in the past 10 years, scientists have begun analyzing DNA methylation to estimate age. 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.
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 estimate 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 an estimate of their calendar age.
“Our goal is to create an Age Test that can work on any dog, no matter their background, breed, or size. That’s why we are collecting DNA methylation data from a diverse panel of dogs. We are creating a model that will convert this information to a predicted age, and we will work to continuously improve our test.”
—Erin Wissink, PhD,
Senior Scientist 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.
To develop our model, we are collecting a large cohort of dogs with known ages. These dogs represent:
- 100+ breeds
- 200+ mixed-breed dogs
- Toy, small, medium, large, and giant dogs
We will then measure the amount of DNA methylation present across all the dogs’ genomes.
We will compare the DNA methylation patterns to the ages of the dogs in the reference panel, and then find regions where methylation changes with age. Using these regions, we will optimize a model that will allow us to estimate a dog’s age.
We will test the performance of our model and calculate the accuracy of the age predictions. After this testing, we will be able to estimate a dog’s age, as well as report how confident we are that the dog’s age falls within a specified range in either direction of the dog’s calendar age.
The chart below shows an example Age Test report. In this example, Oliver’s estimated calendar age is 7 years, 2 months old. His results show a confidence interval of 95%. That means that if we ran Oliver’s DNA on the Age Test 100 times, we would expect that in 95 of those 100 tests, his age result would be between 6 years, 4 months and 8 years.
The chart above shows an example of how confidence levels may appear in Age Test results.
“Predicting age using DNA methylation patterns from cells collected from cheek swabs is a relatively new area of science. Therefore, it’s important that we continuously learn and update our analytical approaches as the science evolves. This will help us improve the precision and accuracy of our Age Test models.”
– Michelle Penny, PhD
Executive Vice President, R&D at Embark
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, but it is possible that nutrition and/or stress may affect our methylation results.
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 the Embark Age Test, you also get access to helpful care information based on your dog’s life stage as they mature from puppy to adult to senior.
Learn more about dog life stages and health considerations to keep in mind as your dog celebrates more birthdays.
