Scientific Results: Epigenetic aging and transposon dysregulation reflect size-related lifespan compression in dogs

October 23, 2026 - 6 minutes read

[vc_row][vc_column][vc_message message_box_color=”violet” icon_fontawesome=”fa fa-paw”]Posts in our Scientific Results series introduce recent papers published in the scientific literature by members of the Dog Aging Project research team. Follow this series to learn more about the scientific questions we’re asking, the kinds of results we’re getting, and what it all means for you and your dog.[/vc_message][/vc_column][/vc_row][vc_row][vc_column][vc_column_text]

Author

Blaise L. Mariner, Brianah M. McCoy

Who worked on this research?

Blaise L. Mariner
Brianah M. McCoy
Ashlee Greenier
Layla Brassington
Elizabeth Slikas
Christine Adjangba
Claire Cheng
Abbey Marye
Benjamin R. Harrison
Tal Bamberger
Yadid Algavi
Efrat Muller
Adam Harris
Emily Rout
Cindy Reichel
Vista Sohrab
The Dog Aging Project Consortium
Elinor Karlsson
Joshua M. Akey
Anne C. Avery
Elhanan Borenstein
Daniel E. L. Promislow
Noah Snyder-Mackler

Where was it published?

Science

What is this paper about?

This study looked at a question many dog owners wondered about: Why do large dogs tend to live shorter lives than small dogs? The researchers wanted to find out whether large dogs simply die younger or whether they actually die faster throughout their lives.

What they did:

The researchers analyzed DNA samples from 894 companion dogs enrolled in the Dog Aging Project’s Precision Cohort, generating more than 1,600 DNA methylation profiles. The Precision Cohort is a group of dogs that contribute more detailed biological samples and health data to help researchers better understand the science of aging. DNA methylation is a type of epigenetic marker that changes with age and can be used to estimate a dog’s “biological age” rather than just its chronological age. Using these data, the team developed an “epigenetic clock” to measure how quickly dogs age at the molecular level.

What they discovered:

The researchers found that large dogs show signs of faster biological aging than small dogs. Their epigenetic clocks indicated that larger-bodied dogs age more rapidly at the molecular level, helping explain why they tend to have shorter lifespans. They also found that dogs whose biological age appeared older than expected had a higher risk of mortality, suggesting that these epigenetic measures reflect meaningful differences in health and aging. 

Another important finding involved transposable elements, sometimes called “jumping genes.” DNA methylation is one of the ways the cell fundamentally regulates transposable element transcription. The researchers observed age-related loss of DNA methylation in these regions, which may allow these jumping genes to become more active. Researchers found this age-related loss of methylation at transposons was more pronounced in larger dogs and may be one of the biological mechanisms contributing to size-associated aging and onset of age-related disease.

What do these results mean for me and my dog?

This study provides some of the strongest evidence yet that large dogs don’t just have shorter lifespans; they actually age faster. In other words, their bodies appear to move through the aging process more quickly than those of smaller dogs.

For members of the Precision Cohort, this finding highlights the important role their dogs’ samples and health information play in helping researchers better understand how and why dogs age. 

For dog owners everywhere, these results offer new insights into the differences in aging across dogs and may help researchers develop better ways to identify age-related health risks and support healthy aging in the future. Because dogs share our homes, lifestyles, and environments, what we learn about aging in dogs may also help us better understand aging in people.

Where can I learn more?

Blaise L. Mariner et al., Epigenetic aging and transposon dysregulation reflect size-related lifespan compression in dogs. Science 394,eaeb2986 (2026). DOI:10.1126/science.aeb2986

Abstract

The extraordinary lifespan variation in domestic dogs provides a natural experiment for testing how intrinsic rates of biological aging shape lifespan. Using 1640 methylomes from 894 dogs, we developed an epigenetic clock that predicted mortality and demonstrated that epigenetic aging is fastest early in life. At orthologs of human age-associated genes, dogs exhibited concordant age effects on promoter methylation, highlighting conserved remodeling of immune pathways. We found that larger and male dogs, which are shorter lived, exhibit accelerated molecular aging. Distinct epigenetic architectures mediated these effects: Sex-dependent methylation changes were concentrated on the X chromosome, whereas size-associated methylation was especially pronounced at transposable elements (TEs). These findings show that epigenetics reflects lifespan differences in dogs and identifies TEs as potential mediators of size-associated lifespan.

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