A team of researchers has developed a formula for converting a dog's age into human years. The proposal is based on the transformation of DNA over time.
According to the study, led by geneticists Tina Wang and Trey Ideker, as humans and dogs grow older, methyl groups are added to our DNA molecules, which can change the activity of a DNA segment without altering it. DNA methylation can be used to measure age in humans, which is called the epigenetic clock.
From there the team of researchers at the University of California San Diego compared the epigenetic clock of humans with that of dogs.
They concluded that a dog's life span can range from six or seven years of large breeds such as mastiffs to 17 or 18 years of younger ones such as chihuahua. Nevertheless, dogs exhibit an identical path of physiological and pathological development.
To reach these results, the researchers drew blood samples from 320 people, aged between one and 103 years, doing the same with 104 Labradors, from four weeks to 16 years.
They found that the similarities were greater when comparing young dogs with younger humans and older dogs with older humans. It was from there that they created the formula: "human age = 16 years In (dog age) + 31". This implies multiplying the dog's natural logarithm in years by 16 and then adding 31. The end result is the age equivalent in human years.
The study is published. bioRxiv preprint file – and there are many comments from owners of the "best friend of man" that question the conclusions.