Background and Aims The dynamics of genome evolution caused by whole genome duplications and other processes are hypothesized to shape the diversification of plants and thus contribute to the astonishing variation in species richness among the main lineages of land plants. Ferns, the second most species-rich lineage of land plants, are highly suitable to test this hypothesis because of several unique features that distinguish fern genomes from those of seed plants. In this study, we tested the hypothesis that genome diversity and disparity shape fern species diversity by recording several parameters related to genome size and chromosome number. Methods We conducted de novo measurement of DNA C-values across the fern phylogeny to reconstruct the phylogenetic history of the genome space occupation in ferns by integrating genomic parameters such as genome size, chromosome number and average DNA amount per chromosome into a time-scaled phylogenetic framework. Using phylogenetic generalized least square methods, we determined correlations between chromosome number and genome size, species diversity and evolutionary rates of their transformation. Key Results The measurements of DNA C-values for 233 species more than doubled the taxon coverage from ~2.2 % in previous studies to 5.3 % of extant diversity. The dataset not only documented substantial differences in the accumulation of genomic diversity and disparity among the major lineages of ferns but also supported the predicted correlation between species diversity and the dynamics of genome evolution. Conclusions Our results demonstrated substantial genome disparity among different groups of ferns and supported the prediction that alterations of reproductive modes alter trends of genome evolution. Finally, we recovered evidence for a close link between the dynamics of genome evolution and species diversity in ferns for the first time.

中文翻译：

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蕨类植物基因组空间占用的演变：连接基因组多样性和物种丰富度

背景和目标 假设由全基因组复制和其他过程引起的基因组进化动力学塑造植物的多样化，从而导致陆生植物主要谱系中物种丰富度的惊人变化。蕨类植物是陆地植物物种第二丰富的谱系，非常适合检验这一假设，因为蕨类植物的基因组有几个独特的特征，可以将蕨类植物的基因组与种子植物的基因组区分开来。在这项研究中，我们通过记录与基因组大小和染色体数量相关的几个参数来检验基因组多样性和差异塑造蕨类物种多样性的假设。方法 我们对蕨类植物系统发育过程中的 DNA C 值进行了从头测量，通过将基因组参数（例如基因组大小、染色体数和每条染色体的平均 DNA 量）整合到时间尺度的系统发育系统中，重建蕨类植物基因组空间占用的系统发育历史框架。使用系统发育广义最小二乘法，我们确定了染色体数量与基因组大小、物种多样性及其转化的进化速率之间的相关性。主要结果 233 个物种的 DNA C 值测量值使分类群覆盖率增加了一倍以上，从之前研究的 2.2% 增加到现存多样性的 5.3%。该数据集不仅记录了基因组多样性积累的实质性差异和蕨类植物主要谱系之间的差异，而且还支持物种多样性与基因组进化动力学之间预测的相关性。结论 我们的结果证明了不同蕨类植物群体之间存在显着的基因组差异，并支持生殖模式的改变会改变基因组进化趋势的预测。最后，我们首次找到了蕨类植物基因组进化动力学与物种多样性之间密切联系的证据。