Whole‐genome duplication (WGD) is a dramatic, common event in plants. Because of the detrimental effects arising from doubling the entire chromosome set, such as minority cytotype exclusion, genomic instability, mitotic and meiotic abnormalities, alterations in cell architecture, or epigenetic changes (Comai, 2005), purifying selection is expected to quickly remove polyploids from the population. Nevertheless, polyploidy is common, and many diploids bear traces of a polyploid ancestry (Soltis et al., 2015; Van de Peer et al., 2017). Some of these ancestral polyploidy events can be traced back to the origin of large and diverse taxonomic lineages; also, most crops are neopolyploids, suggesting an important role for WGDs in promoting phenotypic diversity, speciation, and domestication.

Interestingly, the long‐term fixation of polyploidy does not seem to occur randomly. One notable example is the biased distribution of WGD events across independent plant lineages at the Cretaceous–Paleogene or K‐Pg boundary, about 66 million years ago (Ma). Many lineages seem to have undergone a WGD around the time of the K‐Pg extinction event, while their nonpolyploid ancestors died out, suggesting that polyploidy might confer an adaptive advantage under stressful environments and periods of environmental turmoil (Van de Peer et al., 2017). There might be other examples of “waves” of WGDs during periods of environmental change. For instance, the timing of WGD events in the Malpighiales may correlate with periods of global climatic change during the Paleocene–Eocene, ca. 56–54 mya (Cai et al., 2019). However, the evolutionary mechanisms underlying the relationship between WGD and evolutionary success remain elusive, despite vivid discussions on the topic, as witnessed by a recent special series of review papers and several other essays in the “On the Nature of Things” section of this very same journal. Here, we try to reconcile and discuss some recent findings about the putative adaptive role of WGD during evolution under scenarios of global ecological challenge.

全基因组重复（WGD）是植物中一个戏剧性的、常见的事件。由于将整个染色体集加倍会产生不利影响，例如少数细胞型排斥、基因组不稳定性、有丝分裂和减数分裂异常、细胞结构改变或表观遗传变化（Comai，2005 年），预计纯化选择将快速去除多倍体人口。然而，多倍体是常见的，许多二倍体带有多倍体祖先的痕迹（Soltis 等人，2015 年；Van de Peer 等人，2017 年））。其中一些祖先的多倍体事件可以追溯到庞大而多样的分类谱系的起源；此外，大多数作物是新多倍体，表明 WGD 在促进表型多样性、物种形成和驯化方面发挥着重要作用。

有趣的是，多倍体的长期固定似乎并不是随机发生的。一个值得注意的例子是大约 6600 万年前 (Ma) 白垩纪-古近纪或 K-Pg 边界处独立植物谱系的 WGD 事件的偏向分布。许多谱系似乎在 K-Pg 灭绝事件前后经历了 WGD，而它们的非多倍体祖先灭绝了，这表明多倍体可能在压力环境和环境动荡时期赋予适应性优势（Van de Peer 等人，2017 年）。在环境变化期间，可能还有其他 WGD“波浪”的例子。例如，Malpighiales 中 WGD 事件的时间可能与古新世 - 始新世期间全球气候变化的时期相关，约。56–54 mya (Cai et al.,2019 年）。然而，尽管对这个话题进行了生动的讨论，但 WGD 与进化成功之间关系的进化机制仍然难以捉摸，正如最近的一系列评论论文和本篇“关于事物的本质”部分中的其他几篇文章所证明的那样。同一个杂志。在这里，我们试图调和和讨论最近关于 WGD 在全球生态挑战情景下进化过程中假定的适应性作用的一些发现。