An epigenetic ageing clock in trees

Using trees as a model, researchers of the TUM and of the University of Georgia, USA, have shown for the first time that epimutations accumulate continuously throughout plant development and that this information can be used as a molecular clock to estimate the age of a tree. Image: Robert Schmitz / TUM-IAS Research on environmental history: 330-year-old poplar tree tells of its life - Similar to genetic mutations, epigenetic changes, i.e. gene modifications that do not occur on the primary DNA sequence, sometimes arise accidentally in plants and can be transmitted across generations. Using trees as a model, researchers have now shown for the first time that these so-called epimutations accumulate continuously throughout plant development, and that they can be employed as a molecular clock to estimate the age of a tree. Epigenetic marks do not change the DNA sequence but can affect the activity of genes. "Although in animals, including humans, these marks are believed to be completely reset in gametes, in plants, they can be stably inherited for many generations," says Frank Johannes , Professor of Population epigenetic and epigenomics at the Technical University of Munich (TUM), whose research team has been trying to understand how epimutations arise in plant genomes, how stable they are across generations, and whether they can affect important plant characteristics. "Given their extraordinary longevity, trees act as natural epimutation accumulation systems, and therefore offer unique insights into epigenetic processes over long time-scales," says Professor Johannes.