Calculate Your Dog's Human Age Using This Graph Created by Scientists

Scientists have created a graph based on a new formula which estimates a dog's age in "human years." They say their work published in the journal Cell Systems debunks the commonly held belief that multiplying a dog's age by seven reveals their "human age."

The formula was based on what is known as DNA methylation. Methyl groups are compounds made up of hydrocarbons that attach themselves to DNA and act as signals for turning genes on or off. The rate of the process known as DNA methylation changes as we age.

By mapping how DNA methylation changes in humans and dogs, the researchers created what is known as an epigenetic clock, or biological age based on how genes are expressed. DNA methylation is a type of epigenetic process.

Professor Trey Ideker of the UC San Diego School of Medicine and Moores Cancer Center who co-authored the paper said in a statement that epigenetic changes can reflect a person's age similarly to wrinkles on their face.

The researchers took blood samples from 104 Labrador retrievers aged between 0.1 to 16-years-old and looked at their genetic makeup. They compared their methylation profiles with 320 humans aged between 1 and 103-years-old, and corroborated their findings using mice.

They found the biggest similarities in DNA methylation between younger dogs and younger humans, and older dogs and older humans. There was a strong link between DNA methylation in each species and the different stages of life.

But as dogs age faster than humans in their early years, physiological changes happened in the same sequence but at different timepoints during the lifespan of each species.

dog age, Cell Press, tom hanks,
To calculate your dog's age in "human years" based on epigenetics, find the dog's age along the bottom axis and trace your finger straight up until you reach the red curve. Then trace your finger straight over to the left to find the corresponding human age. Cell Press

For instance, an eight-week-old dog was comparable to 9-month-old, which happens to be when teeth develop in puppies and babies. And a 12-year-old dog was comparable to a 70-year-old human.

Ideker said: "This makes sense when you think about it—after all, a nine-month-old dog can have puppies, so we already knew that the 1:7 ratio wasn't an accurate measure of age."

The results suggest that the DNA methylation can be compared across species as a measure of aging, the team said, and could be built on to find interventions to increase healthspan.

The study was limited, however, as the team only studies Labrador retrievers, and different breeds have different lifespans.