Owls (Strigiformes) evolved specific adaptations to their nocturnal predatory lifestyle, such as asymmetrical ears, a facial disk, and a feather structure allowing silent flight. Owls also share some traits with diurnal raptors and other nocturnal birds, such as cryptic plumage patterns, reversed sexual size dimorphism, and acute vision and hearing. The genetic basis of some of these adaptations to a nocturnal predatory lifestyle has been studied by candidate gene approaches but rarely with genome-wide scans. Here, we used a genome-wide comparative analysis to test for selection in the early history of the owls. We estimated the substitution rates in the coding regions of 20 bird genomes, including 11 owls of which five were newly sequenced. Then, we tested for functional overrepresentation across the genes that showed signals of selection. In the ancestral branch of the owls, we found traces of positive selection in the evolution of genes functionally related to visual perception, especially to phototransduction, and to chromosome packaging. Several genes that have been previously linked to acoustic perception, circadian rhythm, and feather structure also showed signals of an accelerated evolution in the origin of the owls. We discuss the functions of the genes under positive selection and their putative association with the adaptation to the nocturnal predatory lifestyle of the owls.

中文翻译：

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猫头鹰对夜间捕食生活方式的感觉适应的基因组证据。


猫头鹰（Strigiformes）进化出了对其夜间捕食生活方式的特定适应，例如不对称的耳朵、面盘和允许无声飞行的羽毛结构。猫头鹰还与昼行猛禽和其他夜行鸟类具有一些共同特征，例如神秘的羽毛图案、反向的性别大小二态性以及敏锐的视力和听力。一些对夜间捕食生活方式的适应的遗传基础已经通过候选基因方法进行了研究，但很少使用全基因组扫描。在这里，我们使用全基因组比较分析来测试猫头鹰早期历史中的选择。我们估计了 20 种鸟类基因组编码区的替换率，其中包括 11 种猫头鹰，其中 5 种是新测序的。然后，我们测试了显示选择信号的基因的功能过度表达。在猫头鹰的祖先分支中，我们在与视觉感知功能相关的基因进化中发现了正选择的痕迹，特别是与光转导和染色体包装相关的基因。先前与声音感知、昼夜节律和羽毛结构有关的几个基因也显示出猫头鹰起源加速进化的信号。我们讨论了正选择下基因的功能以及它们与猫头鹰适应夜间捕食生活方式的假定关联。