High genetic diversity in an ancient Hawaiian clone

The study is published in New Phytologist.

Among the most long-lived of organisms, every plant of the Hawaiian population appears to have been produced by vegetative rather than sexual propagation and can be traced back to a single parent.

Surprisingly, the genetic diversity of the Hawaiian clone is comparable to that detected in populations of S. palustre that do propagate sexually and occur across vaster regions.

"The genetic diversity of populations occurring on small remote islands is typically much lower than that detected in populations of the same species found on continents and on larger, less isolated islands," said Eric Karlin, a professor at Ramapo College in Mahwah, New Jersey, USA.

As the Hawaiian Islands are the most remote high volcanic island system in the world, the comparatively high genetic diversity detected in the Hawaiian population of S. palustre is unusual.

The occurrence of high genetic diversity in a clone was also "quite unexpected" said Professor Karlin.

This study indicates that significant genetic diversity can develop in a clonal population. It also suggests that vegetative propagation does not necessarily preclude long-term evolutionary success in a plant.

Headed by Professor Karlin, the research team also included colleagues at the University of Wisconsin-Madison (Sara Hotchkiss) in Madison, Wisconsin, USA, Duke University (Sandra Boles, Jonathan Shaw) in Durham, North Carolina, USA, and the Norwegian University of Science and Technology (Hans Stenøien, Kristian Hassel, Kjell Flatberg), in Trondheim, Norway.

Genetic lab work was done at the Duke University Bryology Lab headed by Professor Jonathan Shaw.

Data on the population of S. palustre in eastern North America was provided by a prior study led by Professor Karlin and published in The Bryologist; Ramapo College students Melissa Giusti and Rebecca Lake were among the secondary authors of this prior study. In addition, a grant from the Ramapo College Foundation, which partly funded the Hawaiian project, enabled a third Ramapo College student, Falon Cartwright, to visit the Duke Bryology Lab where she gained experience with genetic analysis.