Global Consortium Creates Large-Scale, Cross-Species Database and Universal 'Clock' to Estimate Age in All Mammalian Tissues
Published:13 Sep.2023 Source:University of California - Los Angeles Health Sciences
Scientists at UCLA David Geffen School of Medicine and UCLA Health led an international research team that published two articles detailing changes in DNA -- changes that researchers found are shared by humans and other mammals throughout history and are associated with life span and numerous other traits. DNA methylation is a mechanism by which cells can control gene expression -- turning genes on or off. In these studies, the researchers focused on DNA methylation differences across species at locations where the DNA sequence is generally the same.
To study the effects of DNA methylation, the nearly 200 researchers -- collectively known as the Mammalian Methylation Consortium -- collected and analyzed methylation data from more than 15,000 animal tissue samples covering 348 mammalian species. They found that changes in methylation profiles closely parallel changes in genetics through evolution, demonstrating that there is an intertwined evolution of the genome and the epigenome that influences the biological characteristics and traits of different mammalian species.
Horvath and the consortium researchers used a subset of the database to study the methylation profiles of 185 species of mammals. Identifying changes in methylation levels that occur with age across all mammals, they developed a "universal pan-mammalian clock," a mathematical formula that can accurately estimate age in all mammalian species. They introduced the concept of an epigenetic clock for age measurement, using human saliva samples, in 2011. Two years later, Horvath demonstrated that cytosine methylation enables the creation of a mathematical model for estimating age across all human tissues. The new work, which describes universal clocks, demonstrates that a single formula can accurately estimate age across mammalian tissues and species.