Contrary to a widespread belief, it is not enough to multiply the age of a dog by seven to determine his / her age in human years. The true ratio changes over time, said Thursday the canadian Institutes of health us (NIH).
A study published in the journal Cell Systems has analyzed the evolving genomes of dogs in the course of their lives and generated a new formula for calculating their old-age.
All mammals, men like dogs, live in the same stages of development: birth, infancy, youth, puberty, adulthood and death.
Scientists have identified brands chemical on the DNA corresponding to these different phases of life. This area of research is called epigenetics.
Molecules called methyl groups attach to a portion of the DNA, causing it to switch in a certain position and pushing it to the next phase of its development.
“For me it’s like when you look at the face of someone and you try to guess his age based on his wrinkles, his gray hair, or other characteristics,” says Trey Ideker of the university of San Diego, who led the study.
“These are similar characteristics, but at the molecular level “, he adds.
Mr. Ideker and his colleagues have studied this chemical process of methylation in 104 labradors retriever, whose ages ranged from a few weeks to 16 years. It was then compared to the process of methylation in humans.
The researchers were thus able to generate a complex formula to calculate adequately the age of the man/dog.
According to it, a puppy of eight weeks was about the age of a human infant of nine months, both being at the stage of their development where the teeth grow.
A labrador has a life expectancy of 12 years on average, which corresponds to 70 years, human life expectancy.
“I like to walk my dog by running, and I have more empathy for him who is six years old now,” says Mr. Ideker, his dog with the equivalent of 60 in human years, according to the formula.
Elain Ostrander, a scientist at the NIH and co-author of the study, notes that she has been driving with labradors, but that more research could include the breeds of dogs with a longer and a shorter life expectancy.
The clock epigenetics may, in particular, assist veterinarians in their decisions for diagnosis and treatment of the animals, concludes the scientific team.