IRP researchers reframe dog-to-human aging comparisons

Thursday, July 9, 2020

Comparing epigenetic differences between humans and domestic dogs provides an emerging model of aging

One of the most common misconceptions is that one human year equals seven dog years in terms of aging. However, this equivalency is misleading and has been consistently dismissed by veterinarians. A recent study, published in the journal Cell Systems, lays out a new framework for comparing dog-to-human aging. In one such comparison, the researchers found the first eight weeks of a dog’s life is comparable to the first nine months of human infancy, but the ratio changes over time. The research used epigenetics, a process by which modifications occur in the genome, as a biological marker to study the aging process. By comparing when and what epigenetic changes mark certain developmental periods in humans and dogs, researchers hope to gain specific insight into human aging as well.

Researchers performed a comprehensive analysis and quantitatively compared the progression of aging between two mammals, dogs and humans. Scientists at the National Human Genome Research Institute (NHGRI), part of the National Institutes of Health, and collaborators at the University of California (UC) San Diego, UC Davis and the University of Pittsburgh School of Medicine carried out the research.

All mammals experience the same overarching developmental timeline: birth, infancy, youth, puberty, adulthood and death. But researchers have long sought specific biological events that govern when such life stages take place. One means to study such a progression involves epigenetics — gene expression changes caused by factors other than the DNA sequence itself. Recent findings have shown that epigenetic changes are linked to specific stages of aging and that these are shared among species.