Recent breakthroughs in the realm of epigenetics, the study of hereditary traits without altering DNA sequences, have uncovered a fascinating revelation: the age of mammals correlates with accumulating epigenetic changes over their lifetimes.
In the context of humans, this discovery has given rise to epigenetic clocks, now widely used as aging biomarkers. These clocks accurately gauge age from birth to death but reset with each new generation.
However, a groundbreaking study, co-led by the University of Georgia, the GEOMAR Helmholtz Centre for Ocean Research Kiel, and the Technical University of Munich, unveils a surprising twist – epigenetic clocks are not exclusive to mammals. They persist across generations in plants. Published in Science, this study demonstrates that plant epigenetic clocks can measure time with incredible precision, spanning decades to centuries, surpassing traditional DNA mutation-based clocks.
This research illuminates previously perplexing microevolutionary queries, including the timing of invasive species introductions and the consequences of human activities since industrialization.
The journey to discovering plant epigenetic clocks began with an investigation into DNA methylation, a crucial epigenetic process, in the branches of a 300-year-old poplar tree. By combining DNA methylation data with branch diameter and age, researchers inferred branch age accurately. Even an uncored branch’s age was estimated solely from DNA methylation data, hinting at the existence of plant epigenetic clocks.
The study experimentally validated these clocks by matching them with known divergence times in A. thaliana, a self-fertilizing plant, and Z. marina, a clonal seagrass, representing two key plant reproduction modes.
In a separate experiment with A. thaliana populations grown over up to 32 generations under various conditions, the research pinpointed a subset of “clock-like” epimutations that precisely tracked pedigrees.
These findings demonstrate that the plant epigenetic clock outperforms DNA mutation-based clocks in dating populations, even accurately dating a North American A. thaliana population of approximately 140 years old.
This novel molecular clock holds the potential to unveil the true age of extensive fern, reed, or seagrass clones, solving a longstanding mystery in plant biology.
In summary, recent research has unveiled the existence of epigenetic clocks in plants, challenging traditional notions of inheritance and evolution. These plant clocks offer unprecedented accuracy in dating and promise to unlock mysteries in the world of botany.
Source: University of Georgia