Archive · 11 Oct 2026
DNA Methylation May Explain Why Large Dogs Age Faster
Dogs have DNA that helps tell their bodies how to work.
DNA methylation acts a bit like switches that help control genes.
As dogs get older, some of these switches become less orderly.
The study found that this change happened more in large dogs than in small dogs.
That may mean large dogs’ cells age faster, even when two dogs are the same number of years old.
The researchers also found faster methylation loss in male dogs than female dogs.
They studied pet dogs living in everyday homes, not just animals in a laboratory.
The findings offer a possible explanation for why large dogs tend to have shorter lives.
An Arizona State University-led study examined 1,640 methylation maps from 894 pet dogs across 120 breeds.
Researchers used DNA methylation, a molecular marker of biological ageing, rather than lifespan alone.
Large dogs showed 31 per cent greater loss of DNA methylation than smaller dogs.
The researchers say methylation loss can affect genome stability and is linked to faster biological ageing.
Male dogs also showed faster methylation loss than female dogs.
- Who
- Researchers from Arizona State University studied 894 pet dogs.
- What
- The study found greater DNA methylation loss in large dogs, which may help explain their faster biological ageing.
- When
- The study was published on 8 October; the article does not specify the year.
- Where
- The research analyzed pet dogs from 120 breeds; the article does not specify the dogs’ locations.
- Why
- Researchers sought to understand why large dogs generally have shorter lifespans than smaller dogs.
Study findings
Limits of the findings
What explains shorter lifespans?
Study findings
The study links faster loss of DNA methylation in larger dogs to faster biological ageing.
Limits of the findings
The article presents this as a possible explanation based on molecular analysis, not proof that methylation loss alone causes large dogs’ shorter lifespans.
- Study sample
- 894 pet dogs
- Methylation maps analyzed
- 1,640
- Breeds represented
- 120
- Publication
- Science, 8 October
- Methylation loss in large dogs
- 31 per cent greater than in smaller dogs
- Other reported difference
- Male dogs showed faster methylation loss than female dogs.