背景回顾：Taxon-specific small RNA loci are widespread in eukaryotic genomes, yet their role in lineage-specific adaptation, phenotypic diversification, and speciation is poorly understood. 

结果：Here, we report that a speciation locus in monkeyflowers (Mimulus), YELLOW UPPER (YUP), contains an inverted repeat region that produces small interfering RNAs (siRNAs) in a phased pattern. Although the inverted repeat is derived from a partial duplication of a protein-coding gene that is not involved in flower pigmentation, one of the siRNAs targets and represses a master regulator of floral carotenoid pigmentation. 

结论：YUP emerged with two protein-coding genes that control other aspects of flower coloration as a “superlocus” in a subclade of Mimulus and has contributed to subsequent phenotypic diversification and pollinator-mediated speciation in the descendant species.

分类群特异性的小RNA位点在真核基因组中广泛分布，但其在谱系特异性适应、表型多样化以及物种形成方面的作用还不清楚。本文中，作者报道了一个在猴面花中的物种形成位点YUP，该位点包含一段能够形成phasiRNAs的反向重复区。尽管该反向重复源自于一个不参与花着色的蛋白编码基因的部分复制，但是其中一个siRNAs能够靶向并抑制花类胡萝卜素着色的关键因子。YUP与其它两个控制花青素着色的蛋白编码基因一起，代表了猴面花一类亚群花色控制的“superlocus”，并且作用于其后代物种的表型多样化和传粉者介导的物种形成。

** 袁耀武 **