A recent study published in the journal Science indicates that larger dog breeds have shorter lifespans compared to smaller breeds, primarily due to accelerated molecular aging in their DNA. Researchers from Arizona State University examined 1,640 blood methylation profiles from 894 dogs to create an 'epigenetic clock' that can predict a dog's biological age with a margin of error of less than one year.
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The study revealed that larger dogs face a faster erosion of DNA methylation in genomic regions that typically keep 'jumping genes' inactive. This increased erosion correlates with a greater risk of genomic instability, cancer, and age-related health issues. Additionally, the research identified noticeable sex-based differences in biological aging; male dogs showed higher methylation in LINE1 elements on their single X chromosome compared to their female counterparts.
Professor Noah Snyder-Mackler, a co-author of the study, noted that selective breeding by humans for rapid growth may have contributed to these late-life molecular challenges. He suggested that future interventions targeting molecular aging could potentially help extend the healthy lifespans of larger dog breeds.