Introduction:
Doggy DNA tests have become increasingly popular due to accessibility and reasonable price points, but can they tell how old a dog is?
Dog ageing has been surrounded by the myth known as the ‘dog years theory,’ which provides a guess-estimation of age. As this isn’t accurate, professionals tend to use their veterinary expertise determining age using physical indicators such as; salt and pepper markings around the eyes and muzzles, slow mobility, lack of teeth, hearing loss, and a general disdain for those young-pups who want to play. Before this, people wondered about their mutts mixes, pedigree cruft dreams, and DNA testing exploded onto the market, highlighting all the weird and wonderful crossbreeds along the way.
Most dog owners wonder about their pup’s age, especially those who have rescues with unknown backgrounds, and some well… we just want to know! As a lover of pooches, I want to maximise my time with my pup and live our best lives together. I have sifted through the science – with exciting results!
Working out if your sweet pup is old enough for pawsecco and horror films – currently cannot be done via a DNA test, but you can find out your dog’s biological age, which is equally scary… (why can’t they just live forever?). HOWEVER, there is a free formula to working out a more accurate chronological age than the one human year to seven dog years method.
But first, more information on the two different types of ageing:
Chronological ageing – For pups with no known DOB, well, the science isn’t there yet, but research looks promising in murine models (mice) using ‘ribosomal DNA’. But, there is a new way of calculating the chronological age of the dog, science approved!
Biological ageing can currently be determined by a DNA test, which can differ wildly from the dog’s chronological age due to ‘DNA Methylation.’ That statement may sound scary, but it is a standard process seen across genus and species and is now used by genetic scientists!
This mechanism is used in the body in a few ways – mainly to control gene expression, but we also see this in cancer studies, where tumour silencing genes get switched off, allowing cancer to grow. So, as we age, the cancer risk increases – this is also seen in dogs. Biological ageing in dogs can be managed by a healthy diet, low stress, appropriate exercise, and stimulation.
Biological age shows how your dog is functioning at a cellular level. Like humans, our dogs’ biological processes are affected by several things: dogs who have come from abusive homes, for example, are more likely to have a higher biological age than their chronological age. Much like humans that have experienced trauma, dogs who have had sad beginnings, the body remembers trauma and internalises it. Stress is one of the significant causes of DNA changes in humans and dogs.
A speckle of joy in 2020 – aka the dumpster fire year that will forever be ingrained in our psyche: In October, scientists confirmed there is current research using ribosomal DNA to determine chronological age, and this technique has been successful in mice. Ribosomes are intracellular structures that churn out protein chains, using information from DNA in the nucleus. They have their own DNA, as do mitochondria (the power-house of the cell) due to their unique functions within a cell that requires autonomy.
Hopefully, this research will hit the mainstream market in the next few years. A dual DNA test that confirms age and breed(s) could revolutionise dog rescuing.
By catering to the dogs’ needs and human preferences – matchmaking forever homes could become far easier and more successful. Like doggy Tinder? If you’re a home-body that likes to snuggle and wants a low exercise pupper, how about a senior greyhound? They are couch potatoes that look fabulous in turtle necks, and *hopefully* their prey drive is lower due to being an old fogey.
Being adopted and then returned to the shelter because it wasn’t a good fit definitely comes under ‘stressful doggy experiences,’ which is precisely what we want to avoid! Creating a safe, healthy, and loving environment for your pooch is tied to their longevity.
Before working out the chronological age of your pup, consider the following:
Did you know that there are age differences between dogs based on size? Toy, small, medium, and large dogs differ in age and longevity. Certain toy/small breeds can live long lives – some up to the ripe old age of 20! Generally, the larger the breed, the shorter the lifespan. Giant breeds such as Great Danes rarely make it past ten years of age. Fret not, as there are accurate calculators that can help estimate your dog’s chronological age using breed and size information. There are also several charts on Pinterest and google if you want to give it a try yourself.
For example, my dog Winston, a crossbreed – Bichon Frise and Lhasa Apso, is considered a small dog. He weighs a healthy 8.8 kg and is three years old. His actual chronological age is 28.
Let’s take a hypothetical large breed into account: A Cane Corso, 50kg and four years old, determined his chronological age is 33.
Why is there such a variation in lifespan?
It seems the canine ancestors – Grey Wolves, were of similar size to one another, so the environment determined the evolutionary changes in size. Environmental changes such as food availability sparked some evolutionary changes, but human interference brought on huge differences spanning over 300 years, which is an incredibly short time-frame from a genetic point of view. Dogs were bred to have specific attributes, and many domesticated dogs had a purpose: the Komondor (they have a thick coat that looks like cords) was initially used to protect sheep in the Hungarian countryside. They are confident and protective, using their coat as a shield from predators. It also helped them blend in with the flock, using the element of surprise to deter wolves and other carnivores.
Who knew that that breeding dogs for specific jobs and traits would affect their lifespan?
Although we cannot currently determine our dog’s age using a DNA test, the online calculators are pretty good for getting an estimation; I’ve linked a few at the end of the article.
The oldest dog in the UK – Queenie, a mixed terrier breed, has been on the Earth for an astonishing 21 years. In dog years, she would have already received a card from HRH, Queenie is 103! Queenie is no longer considered senior but geriatric and is living happily at home with two younger terriers and gets the TLC she deserves after being at the Dog’s Trust for eight years.
An ancient dog was recovered from the Siberian permafrost; carbon dating put him at 18,000 years old – frozen in time at the tender age of 2 months (he still had puppy teeth, aww). The DNA analysis was inconclusive about whether he was a wolf or a dog, which suggests an overlap of wolves and domesticated dog breeds. For more information, see our article ‘How do dog DNA tests work?’ where we explore canine genetics in more detail.
So, to wrap things up – we can confirm biological age by purchasing a DNA test kit or by your Vet at the next check-up. I tried a few calculators for estimating chronological age; pedigree Calculator is simple to use and accessible. The AJdesigner calculator appeals to the scientist in me, as you can adjust parameters, and there’s even a graph. What a time to be alive.
Dog Age Calculators:
https://www.ajdesigner.com/fl_dog_age/dog_age.php
https://www.pedigree.com/dog-care/dog-age-calculator
What type of sample is required for a dog DNA test?
Fortunately, this does not require any pooping or scooping!
Saliva samples or cheek swabs are the usual methods; blood samples can also be used but are generally more expensive.
Cheek swab samples are collected using a little brush; this needs to be rubbed against the cheek for a good 20 seconds. Repeating the swab (most tests provide two brushes) on the other cheek makes it more likely for the lab to get a large enough sample to work from. Most dogs won’t enjoy the sensation. Err on the side of caution if your dog is uncomfortable with you rooting around
in their mouth.
Blood tests will need to be done by a professional, which takes the element of danger away. Again, this may incur a fee, but it could be done on top of the dog’s annual check-up or routine blood work.
Are dog DNA tests accurate?
Dog DNA tests range from approximately 95-99% accuracy; the disparity accounts for human error and test sensitivity. Online tests differ from one another, offering different price points. A lower price point might identify the breed but may not be sensitive enough to derive any further information.
References
https://genetics.thetech.org/original_news/news52
https://genome.cshlp.org/content/29/3/325.short
https://mcb.asm.org/content/40/22/e00368-20.abstract rDNA
https://www.birminghammail.co.uk/news/uk-news/meet-oldest-dog-uk-still-17978247
https://www.easydna.co.uk/dog-genetic-age-test/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3482848/
https://www.pedigree.com/dog-care/dog-age-calculator