背景回顾：Gene duplication is increasingly recognized as an important mechanism for the origination of new genes, as revealed by comparative genomic analysis. 

提出问题：However, how new duplicate genes contribute to phenotypic evolution remains largely unknown, especially in plants. 

主要发现：Here, we identified the new gene EXOV, derived from a partial gene duplication of its parental gene EXOVL in Arabidopsis thaliana.

结果1-EXOV起源与演化：EXOV is a species-specific gene that originated within the last 3.5 million years and shows strong signals of positive selection. 

结果2-EXOV作用于表型演化：Unexpectedly, RNA-seq analyses revealed that, despite its young age, EXOV has acquired many novel direct and indirect interactions in which the parental gene does not engage. This observation is consistent with the high, selection-driven substitution rate of its encoded protein, in contrast to the slowly evolving EXOVL, suggesting an important role for EXOV in phenotypic evolution. 

结果3-EXOV的新功能化：We observed significant differentiation of morphological changes for all phenotypes assessed in genome-edited and T-DNA insertional single mutants and in double T-DNA insertion mutants in EXOV and EXOVL. We discovered a substantial divergence of phenotypic effects by principal component analyses, suggesting neofunctionalization of the new gene. 

结论：These results reveal a young gene that plays critical roles in biological processes that underlie morphological evolution in A. thaliana.

 摘 要 

随着比较基因组学研究的深入，基因复制越来越被认为是新基因起源的重要机制。但是，新复制的基因如何作用于表型的演化在很大程度上还是未知的，尤其是在植物中。本文中，作者在拟南芥中鉴定到了一个来源于EXOVL基因通过部分基因复制产生的新基因EXOV。EXOV是一个物种特异性的基因，大约起源于三百五十万年前，并且存在较强的正选择信号。出乎意料的是，转录组测序显示，尽管EXOV基因比较“年轻”，但是它具有EXOVL基因不曾具备的很多直接或间接互作。这与高水平、选择驱动的碱基替换结果相一致，而EXOVL基因的演化速率较慢，说明了EXOV在表型演化方面的重要性。作者通过基因编辑和T-DNA插入获得了EXOV和EXOVL基因的单突变植株，通过T-DNA插入获得了双突变植株，结果显示这些突变体植株发生了明显的形态学表型分化。作者通过主成分分析发现了野生型、单突和双突植株之间的表型存在的显著分化，说明了EXOV基因发生了新功能化。这些结果揭示了一个年轻的基因在拟南芥的形态演化过程中发挥了重要作用。