The old way to think about your dog’s “human age” — the age in actual yearstimes seven — is wrong. And researchers now have a new formula they think willcalculate your dog’s age more accurately.
Simply put, compared with humans, dogs age very quickly at first, but thentheir aging slows down, a lot.
Trey Ideker of the University of California, San Diego was part of a team ofresearchers that looked at aging on the molecular level.
Humans and dogs have DNA that basically doesn’t change over the course oflife, Ideker says. However, “we have these additional chemical marks, calledepigenetic marks. The particular epigenetic mark that has turned out to bepretty important for the study of age is called methylation,” he says.
“It’s basically a wrinkle on your genome. So you have DNA that does notchange, but then you have these additional marks that do change as you age.And they change in a very predictable way, so that you can use the pattern ofmarks to read out your age.”
The comparison of humans and dogs was made easier because they both often livein similar environments and get similar access to health care.
For the study, they drew the blood of 104 Labrador retrievers ages 4 weeks to16 years.
“All I have to do is take dogs in a certain age group, like in a 1-year-oldage group, and look at what are the most similar molecular profiles in thehumans,” Ideker says. “And what ages those humans are. And it turns out thatif you do that for like a 1-year-old dog, you find that the matching humans atthe molecular profile level are surprisingly old. They’re about 30 years old.”
Using a dog age calculator based on the research, a 2-year-old dog is about 42in human years. But a dog twice as old, 4 years, is roughly equivalent to a53-year-old human. Double it again and an 8-year-old dog is only 64 in humanage.
The researchers broke down their comparison by developmental period:
“Juvenile refers to the period after infancy and before puberty, 2-6 mos. indogs, 1-12 yrs. in humans;
“Adolescent refers to the period from puberty to completion of growth, 6 mos.to 2 yrs. in dogs, approximately 12-25 yrs. in humans;
“Mature refers to the period from 2-7 yrs. in dogs and 25-50 yrs. in humans;
“Senior refers to the subsequent period until life expectancy, 12 yrs. indogs, 70 yrs. in humans.”
For a more personal example, Sadie, NPR’s Peter Breslow’s family dog, is 7 inhuman years. So the Breslow family might have once thought of her as being 49,but now it looks like she’s about 62.
But there’s another way to think about it when we humans get to be about thatage.
“If I’m a 60-year-old,” Ideker says, “wow, I’m a 7-year-old dog!”
Source: Peter Breslow James Doubek
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