Oldest marine plant discovered with the help of a new genetic clock

“Vegetative reproduction as an alternative mode of reproduction is widespread in the animal, fungal, and plant kingdoms,” explains research leader Dr Thorsten Reusch, Professor of Marine Ecology at the GEOMAR Helmholtz Centre for Ocean Research Kiel. These so-called “clonal species” produce genetically similar offspring by branching or budding and often reach the size of a football field or more. However, these offspring are not genetically identical. Researchers form from Kiel, London, Oldenburg, and Davis, California, used this mutation accumulation process to develop a novel molecular clock that can determine the age of any clone with high precision. They applied this novel clock to a worldwide dataset of the widespread seagrass Zostera marina (eelgrass), ranging from the Pacific to the Atlantic and the Mediterranean. In Northern Europe in particular, the team found clones with ages of several hundred years, comparable to the age of large oak trees. The oldest clone identified was 1402 years old and came from the Baltic Sea. This clone reached this advanced age despite a harsh and variable environment. 

These new age and longevity estimates for clonal species fill an important knowledge gap. Particularly in marine habitats, many fundamental habitat-forming species such as corals and seagrasses can reproduce vegetatively, and their clones can become very large. The continuous production of small, genetically identical but physically separated shoots or fragments from the parent clone means that age and size are decoupled in these species. The new study now provides a tool to date these clones with high accuracy. “Such data are, in turn, a prerequisite for solving one of the long-standing puzzles in conservation genetics, namely why such large clones can persist despite variable and dynamic environments,” says Thorsten Reusch. The newly developed clock can be applied to many other species, from corals and algae to plants such as reeds or raspberries. Prof. Dr. Iliana Baums, molecular ecologist at the HIFMB, adds: “We can now apply these tools to endangered corals to develop more effective conservation measures, which we urgently need as unprecedented heat waves threaten coral reefs.”

Further Informationen:

Press release GEOMAR

Original publication:

Yu, L., Renton, J., Burian, A. et al. A somatic genetic clock for clonal species. Nat Ecol Evol (2024). DOI: 10.1038/s41559-024-02439-z