Data from: Polyploid formation shapes flowering plant diversity

Polyploidy, or whole genome duplication, has been an important feature of eukaryotic evolution. This is especially true in flowering plants, where all extant angiosperms have descended from polyploid species. Here we present a broad comparative analysis of the effect of polyploidy on flowering plant diversity. We examine the widely held hypothesis that polyploid flowering plants generate more diversity than their diploid counterparts, by fitting stochastic birth/death models to observed ploidal frequency data from 60 extant angiosperm genera. Our results suggest the opposite, that diploids speciate at higher rates than polyploids, through a combination of simple diploid speciation and tetraploidy. Importantly, the estimated diploid advantage stemmed primarily from a higher rate of polyploidization in diploids than polyploids. Our model is also able to account for the empirically observed correlation between polyploidy and species richness without assuming that polyploids have a speciation advantage over diploids.

多倍化（polyploidy），即全基因组复制，一直是真核生物演化的重要特征。这一点在开花植物中尤为显著，所有现存的被子植物（angiosperms）均起源于多倍体物种。本研究针对多倍化对开花植物多样性的影响开展了大规模比较分析。我们通过将随机生灭模型拟合至来自60个现存被子植物属的观测倍性频率数据，检验了当前广为接受的假说：多倍体开花植物相较于其二倍体同类可产生更多的物种多样性。但我们的研究结果却与之相反：相较于多倍体，二倍体的物种形成速率更高，这一现象源于单纯二倍体物种形成与四倍化（tetraploidy）的共同作用。值得注意的是，估算得到的二倍体优势主要源于二倍体相较于多倍体具有更高的多倍化发生率。本模型无需假设多倍体相较于二倍体具有物种形成优势，即可解释实证观测到的多倍化与物种丰富度之间的相关性。