Chemical tags on dogs’ blood DNA were linked to age
In a cross-sectional study of 16 healthy Australian shepherds aged 1–9, older age was linked to fewer chemical tags on repetitive DNA.
Limit: The primary analysis excluded two samples with inconsistent test results
Edited by Boris Djordjevic · AgingResearch.News
Researchers studied DNA circulating in blood from 16 clinically healthy Australian shepherd dogs aged 1–9 in a cross-sectional observational study. They measured methylation, chemical tags attached to DNA, at a site in LINE-1, a repetitive DNA sequence. Older age was strongly associated with lower methylation. A curved relationship fit the data better than a straight line. The primary analysis excluded two samples with inconsistent test results; including them preserved the negative association.
The researchers also examined DNA from the prefrontal cortex, a brain region, in 16 dogs of various breeds. Seven older dogs aged 160–222 months had lower LINE-1 methylation than nine younger dogs aged 10–50 months.
Why it matters
The authors suggest that LINE-1 methylation in circulating DNA may be a candidate minimally invasive marker of chronological aging in dogs.
Caveats
Cross-sectional comparisons studied different dogs rather than following the same dogs as they aged. The blood samples came from one breed and did not include its oldest age group.
The paper
LINE-1 CpG methylation in canine blood and cortical DNA tracks epigenetic changes with age
Eötvös Loránd University
GeroScience, Jul 27, 2026, Open access
