Polyploidy and genome evolution in the common cordgrass Spartina anglica: an enigmatic evolution of allopolyploidy

Abstract

Hybridization and polyploidy represent major features of Spartina (cordgrass) evolution, and the recent formation of the common cordgrass Spartina anglica is one of the most striking examples of allopolyploidy speciation. S. anglica originated in the nineteenth century in Western Europe through hybridization between S. alterniflora (an American native) and S. maritima (a European native). The resulting F1 hybrid, S. x townsendii, underwent genome doubling, leading to the formation of S. anglica. The species has attracted much interest as a useful model system in the context of polyploid evolution and biological invasion. However, several aspects of the evolution of S. anglica are complicated and poorly understood. In this review, we examine the evolutionary history of S. anglica after nearly a century and a half since its discovery. We provide the current state of knowledge regarding its history, polyploid origin, and evolutionary dynamics following polyploidization. Recent findings using molecular approaches have demonstrated that the S. anglica genome has undergone rapid structural and transcriptomic changes. This realization has shattered earlier perceptions of S. anglica as a genetically depauperate species, thus showing that this system is more complicated than previously thought and raising several questions regarding the evolution of this species. We discussed these issues in depth and demonstrated that S. anglica will continue to provide a unique and exceptional avenue for gaining valuable insight into the early stages of species evolution.

Key words:

• Allopolyploidy
• genome evolution
• neopolyploidy
• Spartina. Systematics
• transcriptomic changes

Acknowledgements

The authors are thankful to Sangmyung University, Seoul 03016, South Korea for providing the necessary facilities to carry out the work.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Associate Editor: Dr Maria Vorontsova