Abstract:
Whole-genome duplications (WGDs) or polyploidy events have been studied extensively in plants. In a now
widely cited paper, Jiao et al. presented evidence for two ancient, ancestral plant WGDs predating the origin
of flowering and seed plants, respectively. This finding was based primarily on a bimodal age distribution of
gene duplication events obtained from molecular dating of almost 800 phylogenetic gene trees. We reanalyzed
the phylogenomic data of Jiao et al. and found that the strong bimodality of the age distribution may be the
result of technical and methodological issues and may hence not be a “true” signal of two WGD events. By using
a state-of-the-art molecular dating algorithm, we demonstrate that the reported bimodal age distribution is not
robust and should be interpreted with caution. Thus, there exists little evidence for two ancient WGDs in plants
from phylogenomic dating.