Researchers have come up with a new, and more accurate way, to convert dog years to human years. The formula that many of us are familiar with was based on a simple calculation of one dog year equaling seven human years. But this new approach is a lot more accurate and is based on the actual chemical modifications to a person’s (human or dog) DNA over a lifetime that create an epigenetic clock. Dogs and humans, along with many other species undergo a DNA methylation process as they age. A team of scientists from the University of California, San Diego who are studying aging and how these clocks differ across species, started their research with dogs. “Although humans and dogs diverged early during mammalian evolution dogs share nearly all aspects of their environments with humans. These include, critically for these studies, similar levels of health observation and health care intervention.” Their assumption is that all dogs, regardless of breed, follow a similar developmental trajectory, with puberty reached at 10 months and dying before 20 years. The team focused on Labrador Retrievers, because they were hoping to increase their chances of finding genetic factors associated with ageing by concentrating on just one breed.
The researchers found “that this function showed strong agreement between the approximate times at which dogs and humans experience common physiological milestones during both development and lifetime aging, i.e. infant, juvenile, adolescent, mature, senior.” This translates into a seven-week-old pup equaling that of a nine-month-old child—a time by which deciduous teeth erupt in both pups and babies. They did find that dogs and humans do have similar age-related methylation of certain genomic regions, especially during aging in both species. The team also developed a new epigenetic clock and a formula for calculating it. The dog’s age must be greater than one year, then that age is converted into a natural logarithm and that log is multiplied by 16, and then 31 added for a total. For example, if a dog is 14 years old, the natural log of 14 is 2.6390, multiplying that by 16 equals 42.224, adding 31 brings it to 73.2.
An article in Science about this research also mentioned another group that is studying the aging process of dogs, called Dog Aging Project. It is currently collecting data from pet dogs of citizen scientists. The goal of this project is to understand how genes, lifestyle, and environment influence aging and is a collaborative effort of the University of Washington and Texas A&M University. They hope to see why some dogs develop diseases at younger ages and die earlier, while others like, hopefully, my 14-year-old Lola, lead a mostly disease-free life. I always knew that Lola and I had much in common, that now includes having similar epigenetic ages (see the above calculation).
See how you can nominate your dog for this important project.