The dynamic nature of polyploid genomes.

Abstract

It is well known that polyploidy is a major force in evolution, particularly in plants. Perhaps 50% of all angiosperms are of polyploid origin; estimates for the ferns and fern allies range from 44 to 95% (1, 2). Because of the significant role that it has played in plant evolution, polyploidy has been the focus of great interest and controversy for >50 years. Diverse aspects of polyploidy have been reviewed, including types of polyploids (3-8), ecological and evolutionary attributes of polyploids (810), genetic consequences of polyploid evolution (10-17), and mode of polyploid formation (4, 18, 19). The application of molecular techniques has dramatically increased our understanding of polyploid evolution and has fundamentally reshaped traditional views. The paper by Song et al. (20) in this journal further elucidates the process of polyploid evolution and represents a key breakthrough in our understanding of the evolution of polyploid genomes. To appreciate the great significance of the paper by Song et al. (20), it is important to consider briefly some of the traditional tenets of polyploid evolution.