The secrets of accelerated aging in pet dogs lie in the 'disorder' of their genomes and in the living environment of each country.
Background
Reading the time of pet dogs with a biological clock
Pet dogs share the same living space as humans and are exposed to similar stressors. As a result, they are considered valuable animal models for tracking human aging pathways and understanding disease mechanisms. In recent molecular biology, attention has been focused on biological age, which is measured by changes in the epigenome, rather than chronological age. A key indicator is DNA methylation (DNAm), which regulates gene expression. During the aging process, DNA methylation patterns may change in a specific direction, but at the same time, they also undergo 'epigenetic drift,' which is an increase in random variability. This leads to a phenomenon in which the methylation status of the genome becomes unstable and disordered, which is called epigenetic entropy. However, it has not been clearly elucidated how the rearing country or environmental differences are specifically related to the aging rate and genomic instability of pet dogs.
Key Findings
Accelerated aging and genomic disorder in Korean pet dogs
A research team led by Professor Jae-min Kim of the Department of Animal Life and Biotechnology at Gyeongnam National University, and Professors Seong-rim Lee and Yong-ho Choi of the College of Veterinary Medicine, compared DNA methylation data from 824 pet dogs in Korea and the United States. The research team adopted an epigenetic clock, a pet dog-specific biological age measurement model, as an analysis tool. The biological age recorded a high correlation of r = 0.98 with the actual age. When the aging rate of dogs of the same breed was compared by country, an interesting difference was observed. The epigenetic age acceleration (EAA) of pet dogs in Korea was statistically significantly higher than that of pet dogs in the United States, indicating that Korean pet dogs are biologically aging faster. The research team tracked genomic disorder using a methylation entropy technique. The research team explained that the overall genomic disorder gradually increases. This epigenetic drift follows a different trajectory depending on the size of the pet dog. When comparing groups of small dogs (less than 10 kg), medium-sized dogs (10 to 25 kg), and large dogs (25 kg or more), the rate of entropy increase was steeper for larger dogs. This suggests that the characteristic of short lifespan in large dogs is directly related to the rapid disorder of the genome. In addition, differences in aging trajectories according to sex were also confirmed. The research team newly identified nine aging-related DNA methylation sites that reflect the domestic pet dog environment, and they expect that these sites will serve as indicators of environmental factors.
Significance and Prospects
Environmental factors leave a biological imprint
This study biologically demonstrates that the genomic aging of pet dogs can be greatly affected not only by innate factors but also by acquired living environment. The rearing environment of pet dogs in Korea and the United States differs in various aspects, such as housing type, walking frequency, and feed composition. In particular, it is highly likely that the living characteristics of Korea, where the proportion of indoor living in apartments is high, have affected the epigenome. This is strong evidence supporting the hypothesis in the academic community that environmental stress factors leave traces on DNA methylation marks and regulate the aging rate. In addition, the nine aging-related DNA methylation sites discovered this time are expected to be used as tools for tracking epigenetic changes caused by environmental factors. By using these markers, it will be possible to verify the harmfulness of environmental stress on biological age. However, since it is a retrospective analysis using existing data, a prospective cohort study should follow in the future to observe changes in aging rate by controlling specific environmental factors.
Proceedings of the National Academy of Sciences, Volume 123, Issue 29, July 2026. SignificanceEpigenetic aging involves both directional DNA methylation changes and increasing variability across the genome, but how these dimensions relate remains unclear in dogs. Here, we combine entropy-based and CpG-level variance analyses to examine ...
This study provides practical tools that can be directly applied to the pet industry and clinical veterinary medicine. The most representative application scenario is the development of a 'personalized aging prediction kit' for pet dogs. By utilizing the nine Korean pet dog-specific DNA methylation sites discovered by the research team, it will be possible to accurately measure the biological aging rate of individual pet dogs through a simple blood or saliva test. This is expected to be used as a reference for prescribing customized functional feeds or designing exercise programs for pet dogs with fast aging rates. Furthermore, it can be used as an objective evaluation index to prove the efficacy of anti-aging candidate substances in veterinary clinical trials. This is a method of quantitatively demonstrating at the genome level whether a specific drug or dietary therapy actually slows down the biological age acceleration. In addition, the data from the pet dog aging model will serve as a bridge to accelerate research on preventing premature aging and chronic diseases in humans due to environmental factors.