Males and females of the same species share the majority of their genomes, yet they are frequently exposed to conflicting selection pressures. Gene regulation is widely assumed to resolve these conflicting sex-specific selection pressures, and although there has been considerable focus on elucidating the role of gene expression level in sex-specific adaptation, other regulatory mechanisms have been overlooked. Alternative splicing enables different transcripts to be generated from the same gene, meaning that exons which have sex-specific beneficial effects can in theory be retained in the gene product, while exons with detrimental effects can be skipped. However, at present, little is known about how sex-specific selection acts on broad patterns of alternative splicing. Here we investigate alternative splicing across males and females of multiple bird species. We identify hundreds of genes that have sex-specific patterns of splicing, and establish that sex differences in splicing are correlated with phenotypic sex differences. Additionally, we find that alternatively spliced genes have evolved rapidly as a result of sex-specific selection, and suggest that sex differences in splicing offer another route to sex-specific adaptation when gene expression level changes are limited by functional constraints. Overall, our results shed light on how a diverse transcriptional framework can give rise to the evolution of phenotypic sexual dimorphism.

中文翻译：

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性别特异性选择推动了鸟类选择性剪接的进化。


同一物种的雄性和雌性共享大部分基因组，但它们经常面临相互冲突的选择压力。人们普遍认为基因调控可以解决这些相互冲突的性别特异性选择压力，尽管人们非常关注阐明基因表达水平在性别特异性适应中的作用，但其他调控机制却被忽视了。选择性剪接使得同一基因能够产生不同的转录本，这意味着理论上具有性别特异性有益作用的外显子可以保留在基因产物中，而具有有害作用的外显子可以被跳过。然而，目前人们对性别特异性选择如何作用于广泛的选择性剪接模式知之甚少。在这里，我们研究了多种鸟类雄性和雌性之间的选择性剪接。我们鉴定了数百个具有性别特异性剪接模式的基因，并确定剪接中的性别差异与表型性别差异相关。此外，我们发现选择性剪接基因由于性别特异性选择而迅速进化，并表明当基因表达水平变化受到功能限制时，剪接中的性别差异提供了另一种性别特异性适应途径。总的来说，我们的结果揭示了多样化的转录框架如何引起表型性二态性的进化。