JUL 05, 2020 10:38 AM PDT

A New Way to Estimate a Dog's Age

WRITTEN BY: Carmen Leitch

People have long thought that a dog's age can be estimated by substituting one dog year with seven human years. Recently it's been suggested that a dog's age is dependent on its breed and size, with younger dogs tending to have longer lifespans than very large dogs. Recent research reported in Cell Systems has now suggested that the most accurate way to calculate the age of a dog is by using a mathematical formula that takes into account how a dog's DNA has changed over time.

Image credit: Pixabay

Dogs get age-related illnesses like people do. However, at the molecular level, dogs tend to age quickly when they're younger and their aging rate slows as they get older.

"In terms of how physiologically mature a one-year-old dog is, a nine-month-old dog can have puppies. Right away, you know that if you do the math, you don't just times seven," said the senior study author Trey Ideker of the University of California, San Diego. "What's surprising is exactly how old that one-year-old dog is--it's like a 30-year old human."

The epigenetics of DNA, chemical tags that are added to the genome and can influence gene expression, can change over time. One common epigenetic marker is called methylation, in which a methyl is added to the genome.

In this work, the methylation patterns in 104 Labrador retrievers of various ages were assessed and compared to those seen in humans. This showed that canines and humans have life stages that can be compared in the following mathematical formula: human age = 16 ln(dog age) + 31. For example, a nine-month-old baby is has the equivalent age of an eight-week-old dog. This is when both organisms form teeth. Labrador retrievers have a life expectancy of about twelve years, the human equivalent of 70.

"I like to take my dogs on runs, and so I'm a little bit more sympathetic to the six-year-old now," says Ideker, who used the formula to determine that his dog is nearly 60.

The formula contains the natural logarithmic function ln, so as dogs reach their late teens, their human equivalent doesn't change that much. At 15, a dog is about the age of 74 in humans but when the dogs reach 16 it's only added one 'human' year to make them about equal to age 75.

The methylation changes seemed to occur mostly in genes that are related to development. Once adulthood comes, "you've largely shut off these genes, but they're still smoldering. If you look at the methylation marks on those developmental genes, they're still changing," said Ideker.

The research team created a developmental clock of sorts that can measure age and physiology in different species. Other processes used to estimate age based on methylation tend to only work with one species.

Sources: AAAS/Eurekalert! via Cell Press, Cell Systems

About the Author
  • Experienced research scientist and technical expert with authorships on 28 peer-reviewed publications, traveler to over 60 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
JUN 30, 2020
Plants & Animals
Consequences of Sixth Mass Extinction Threaten Humanity
JUN 30, 2020
Consequences of Sixth Mass Extinction Threaten Humanity
Many scientists have taken note of the rapid decline many of the world species, and several have declared that Earth's s ...
AUG 05, 2020
Plants & Animals
Scientists Discover Record-Breaking Rodent
AUG 05, 2020
Scientists Discover Record-Breaking Rodent
In a year of extremes, researchers have also unveiled a new record-breaking animal—the highest dwelling mammal on ...
AUG 24, 2020
Plants & Animals
Active Dogs Are Less Fearful But Breed is Also a Major Factor
AUG 24, 2020
Active Dogs Are Less Fearful But Breed is Also a Major Factor
Most dog owners are familiar with some common triggers of anxiety and fear in their pets, like new situations, loud nois ...
SEP 27, 2020
Plants & Animals
In a Surprise, Tarantulas Seem to Have Color Vision
SEP 27, 2020
In a Surprise, Tarantulas Seem to Have Color Vision
The image by Bastian Rast shows a Cobalt Blue Tarantula (Hapolpelma lividum), with brilliant cobalt blue hair-like setae ...
OCT 15, 2020
Plants & Animals
Meet the World's First Cloned Przewalski's Horse
OCT 15, 2020
Meet the World's First Cloned Przewalski's Horse
Say “hello!” to Kurt, a two-month-old Przewalski’s horse that has made scientific history as the world ...
OCT 19, 2020
Plants & Animals
Genetically Engineered Foods Could Alleviate Nutritional Deficiencies
OCT 19, 2020
Genetically Engineered Foods Could Alleviate Nutritional Deficiencies
There are over two billion people around the world that don't get the recommended levels of minerals and vitamins in ...
Loading Comments...