A research team from the University of California, San Diego School of Medicine has developed a more accurate formula to calculate a dog’s age — it’s based on the chemical changes in DNA as organisms age
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It’s been used for decades to calculate a dog’s age compared to a human – but new research has completely disproved it.
Researchers at the University of California, San Diego School of Medicine claim that a “human year” is not equal to seven “dog years,” but rather 30.
In an article in the journal Cell System, the team explains how they developed a more accurate formula to calculate a dog’s age based on the chemical changes in DNA as organisms age.
Dogs share the same environment as their owners and receive almost the same standard of health care as humans, giving scientists a unique opportunity to understand aging across species.
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Like humans, dogs follow similar developmental paths that make them more susceptible to age-related diseases over time.
However, how they age at the molecular level is more complicated – they age quickly at first and then slow down later in life.
Senior author Trey Ideker of the University of California said: “In terms of how physiologically mature a one-year-old dog is, a nine-month-old dog can have puppies. You know right away that when you do the math, you’re not just doing seven times.
“What’s surprising is exactly how old this one-year-old dog is – he’s like a 30-year-old human.”
While human and canine DNA don’t change significantly over the course of life, the chemical marks on the DNA, called methylation marks, do.
Ideker views these markers as folds in the genome.
“I tend to think of it as looking at someone’s face and guessing their age based on their wrinkles, gray hair and other characteristics,” he said. “These are just similar features at the molecular level.”
The researchers studied 104 Labrador retrievers, ranging from puppies a few weeks old to dogs as young as 16, with the help of two canine experts, Danika Bannasch of the University of California, Davis, and Elaine Ostrander of the National Institutes of Health. They compared the changes in the methylation pattern with humans.
The comparison yielded a new formula that better fits the canine-human life stages: human age = 16 in (dog age) + 31. Based on the new feature, an eight-week-old dog is approximately a nine-month-old baby, both located in the infancy stage when puppies and babies develop teeth.
The average life expectancy of Labrador Retrievers of 12 years corresponds to the worldwide human life expectancy of 70 years.
“I like to take my dogs with me when I go out, so I have a little more understanding for the six-year-old now,” says Ideker, who noted that his dog is going to be 60 according to the new calculation.
In both species, they found that most of the age-related methylation occurs in developmental genes, which are fired to create body plans in the uterus and regulate infant development.
By the time you become an adult and stop growing, “you’ve largely turned off those genes, but they’re still smoldering,” says Ideker. “If you look at the methylation marks on these developmental genes, they’re still changing.”
Focusing on the smoldering developmental genes, the team developed a clock that can measure the age and physiological state of different species, while other methylation-quantifying age prediction methods only work well in one species.
Ideker also noted that future research on different dog breeds with different lifespans could provide more insight into the new watch.
Not only can the watch serve as a tool to understand cross-species aging, but it can also serve as a clinical practice for veterinarians to take proactive steps to treat animals.
https://www.mirror.co.uk/news/weird-news/experts-disprove-one-year-equivalent-27038560 Experts disprove that one year is equal to seven dog years - it's much longer