How old is your dog in human years? The new formula is much more accurate

The formula is a new “epigenetic clock” – a method for determining the age of a cell, tissue or organism based on reading its epigenetics. (CREDIT: Creative Commons)

If there is one myth that has persisted for years without much evidence, it is this: multiply your dog’s age by seven to calculate how old it is in “human years.” In other words, according to the old adage, a four-year-old dog is close in physiological age to a 28-year-old human.

But a new study from UC San Diego School of Medicine throws that out the window. Instead, they created a formula that more accurately compares the age of humans and dogs.

The formula is based on the change in the structure of methyl groups in the genomes of dogs and humans – how many of these chemical marks and where they are located – with age. Since the two species do not age at the same rate over their lifetime, it turns out that this is not a perfectly linear comparison, as the 1:7 rule of thumb suggests.

The new methylation-based formula, published in Cell Systems, is the first formula that can be transferred between species. More than just a salon gimmick, the researchers say it could be a useful tool for veterinarians and for evaluating anti-aging interventions.

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To calculate your dog’s age in “human years” based on epigenetics, find your dog’s age on the bottom axis of the chart on the right and drag your finger straight up until you reach the red curve. Then swipe right to the left to find the corresponding human age.

“There are a lot of anti-aging products out there these days — with vastly different degrees of scientific backing,” said senior author Trey Ideker, Ph.D., professor at UC San Diego School of Medicine and Moores Cancer Center. “But how do you know if a product will really extend your life without waiting 40 years or so? What if you could instead measure your age-specific methylation patterns before, during, and after the intervention to see if it does anything?” Ideker led the research along with first author Tina Wang, PhD, who was a graduate student in Ideker’s lab at the time.

The formula provides a new “epigenetic clock,” a method of determining the age of a cell, tissue or organism based on reading its epigenetics – chemical modifications such as methylation that affect which genes are “turned off” or “on” without changing them. the inherited genetic sequence itself.

Dog Age Calculator (LETTER: UC San Diego)

According to Ideker, epigenetic changes give scientists clues to the age of the genome, just as wrinkles on a person’s face give clues to their age.

Equation: 16 ln (dog age) + 31 = human age.

For iPhone calculators that have a natural log or “ln” function, enter the dog’s age first. Then press the “ln” button. Multiply this result by 16; then add 31.

If you are using Google Scientific Calculator: Press “ln” first, then enter the dog’s age, and then equalize. Then multiply by 16 and then add 31.

Using this equation:

• A 1 year old dog looks like a 31 year old human;

• A 3 year old dog looks like a 49 year old human;

• A 7 year old dog looks like a 62 year old human.

By this time, the aging of dogs has slowed down, so an 8-year-old dog is like a 64-year-old human.

Idecker and others have previously published epigenetic clocks for humans, but they are limited in that they can only be accurate for the specific people for whom the formulas were developed. They do not transfer to other species, perhaps even to other people.

Idecker said that it was Wang who first gave him the idea of ​​a dog. “We’re always looking at people, but people are pretty boring,” he said. “So she convinced me that we should study dog ​​aging in a comparative way.”

To do this, Idecker and Wang collaborated with canine genetics experts Danika Bannash, DVM, Ph.D., professor of population health and reproduction at UC Davis School of Veterinary Medicine, and Elaine Ostrander, Ph.D., head of cancer genetics and comparative genomics at UC Davis. California. National Institute for Human Genome Research, part of the National Institutes of Health. Bannash provided blood samples from 105 Labrador Retrievers. As the first person to sequence the dog genome, Ostrander made valuable contributions to its analysis.

According to Ideker, dogs are an interesting animal to study. Considering how closely they live with us, perhaps more than any other animal, dogs’ exposure to the environment and chemicals is very similar to humans, and they receive almost the same level of medical care.

It’s also important that we better understand their aging process, he said, as veterinarians often use the old 1:7-year ratio to determine a dog’s age and use that information to make diagnostic and treatment decisions.

The result of the research is a graph that can be used to compare your dog’s age to a comparable human age. The comparison is not a 1:7 ratio in time. Especially when dogs are young, they age quickly compared to humans.

“It makes sense when you think about it — after all, a nine-month-old dog can have puppies, so we already knew that a 1:7 ratio is not an accurate indicator of age,” Ideker said.

One limitation of the new epigenetic clock, Idecker says, is that it was designed using a single breed of dog, and some dog breeds are known to live longer than others. More research will be needed, but because it’s accurate for humans and mice, as well as Labrador Retrievers, he predicts the watch will apply to all dog breeds.

The researchers then plan to test other dog breeds, determine if the results hold up using saliva samples, and test mouse models to see what happens to their epigenetic markers when you try to extend their lifespan with different interventions.

Meanwhile, Ideker, like many other dog owners, now has a slightly different view of his own canine companion.

“I have a six-year-old dog – she still runs with me, but now I understand that she is not as ‘young’ as I thought,” Ideker said.

For more science and technology news, visit our New Innovations section at The bright side of the news.

Note. Materials courtesy of UC San Diego Health above. Content can be edited for style and length.

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