Small changes in the regulatory mechanisms of DNA expression show correlations with chronological age, sex, and lifespan, according to new research presented at the virtual American Society of Human Genetics 2021 Annual Meeting (October 18-22). These findings open new avenues for studying longevity and further our understanding of the role of epigenetics in mammalian evolution and biologic processes involved in aging and lifespan. Epigenetic changes, unlike genetic changes, affect the way genes work without changing the DNA sequence. One common epigenetic mechanism used by cells to control gene activity involves the methylation of specific DNA letters (bases). DNA methylation levels change with age and have been linked to longevity in many animal models. Now, on October 18, 2021, a team led by Amin Haghani, PhD, a geneticist at the University of California, Los Angeles (UCLA), reported the results of an investigation into DNA methylation across more than 200 mammalian species, ranging from the small and short-lived to the massive and long-lived. Analyses of this dataset allowed the researchers to identify correlations between DNA methylation and various traits within and across species of mammals, such as chronological age, sex, and maximum lifespan. The title of Dr. Haghan et al.’s abstract is “DNA Methylation Patterns Underlying Lifespan Differences in Mammals.”