Gene duplication provides raw material for functional innovation, but gene duplicability varies considerably. Previous studies have found widespread asymmetrical sequence evolution between paralogs. However, it remains unknown whether the rate of evolution among paralogs affects their propensity of being retained after another round of whole-genome duplication (WGD). In this study, we investigated gene groups that have experienced two successive WGDs to determine which of two older duplicates with different evolutionary rates was more likely to retain both younger duplicates. To uncouple the measurement of evolutionary rates from any assignment of duplicate or singleton status, we measured the evolutionary rates of singleton genes in out-lineages but classified these singleton genes according to whether they are retained or not in a crown group of species. We found that genes that retained younger duplicates in the crown group of genomes were more constrained prior to the younger duplication event than those that failed to leave duplicates. In addition, we also found that the retained clades have more genes in out-lineages. Subsequent analyses showed that genes in the retained clades were expressed more broadly and highly than genes in the singleton clades. We concluded that the set of repeatedly retained genes after two WGDs is biased toward slowly evolving genes in angiosperms, suggesting that the potential of genes for both functional conservation and divergence likely affects their propensity of being retained after WGD in angiosperms.

中文翻译：

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被子植物基因组中成对重复的缓慢进化基因的优先保留

基因复制为功能创新提供了原材料，但基因复制性差异很大。以前的研究发现旁系同源物之间存在广泛的不对称序列进化。然而，尚不清楚旁系同源物之间的进化速度是否会影响它们在另一轮全基因组复制（WGD）后被保留的倾向。在这项研究中，我们调查了经历过两次连续 WGD 的基因组，以确定具有不同进化速率的两个较老的重复中哪一个更有可能保留两个较年轻的重复。为了将进化率的测量与任何重复或单例状态的分配分开，我们测量了外系中单例基因的进化率，但根据它们是否保留在冠群中对这些单例基因进行分类。我们发现在基因组冠组中保留较年轻重复的基因在较年轻的重复事件之前比那些未能留下重复的基因受到更多限制。此外，我们还发现保留的进化枝在外系中具有更多的基因。随后的分析表明，保留进化枝中的基因比单一进化枝中的基因表达更广泛和更高。我们得出的结论是，在两次 WGD 之后重复保留的基因集偏向于被子植物中缓慢进化的基因，