On Jul. 9, 2020, a study, published in the journal Cell Systems(link is external), laid out a new framework for comparing dog-to-human aging. The researchers found the first eight weeks of a dogﾒ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.