The methylated genomic base N6-methyladenine (6mA) has been found in the genomes of bacteria and small eukaryotic organisms such as ciliates and algae but not in higher organisms, and its function in eukaryotes has been unknown. Now, researchers have found it in two higher organisms and have determined a functional role in algae. Eric Lieberman Greer and Yang Shi of Harvard Medical School and coworkers found 6mA in worms; Hailin Wang and Dahua Chen of the Chinese Academy of Sciences, Beijing, and colleagues discovered it in fruit flies; and a group led by Chuan He of the University of Chicago studied its role in algae (Cell 2015, DOIs: 10.1016/j.cell.2015.04.005, 10.1016/j.cell.2015.04.018, and 10.1016/j.cell.2015.04.010). He and coworkers found that 6mA is widely distributed between DNA-packaging units in the algal genome, suggesting that it regulates gene expression. Epigenetics expert Thomas Carell of Ludwig Maximilian University of Munich comments that the findings emphasize that modified bases have important regulatory functions and are more widespread than was previously thought.