The Shared Genome Is a Pervasive Constraint on the Evolution of Sex-Biased Gene Expression
The Shared Genome Is a Pervasive Constraint on the Evolution of Sex-Biased Gene Expression
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DOI：
10.1093/molbev/mst121
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发表时间：
2013-09-01
影响因子：
10.7
通讯作者：
Friberg, Urban
中科院分区：
文献类型：
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作者：
Griffin, Robert M.;Dean, Rebecca;Friberg, Urban
男性和女性共享大部分基因组，因此性别之间的差异不能通过蛋白质编码基因的序列差异而进化。相反，性别二态性仅限于通过性别特异性表达和基因产物剪接发生。然而，当两性共享基因表达调控的遗传结构时，通过这些机制进行的两性二态性的进化也应该受到限制。尽管存在这些障碍，性二态性在动物界仍然普遍存在，并且通常进化迅速。在这里，我们要问的是，基因表达的遗传结构是否是可塑的，并且很容易通过性别特异性选择来塑造，或者性别二态性是否在普遍的遗传限制下迅速进化。为了解决这个问题，我们探讨了基因表达的两性遗传相关性（r（MF））与性别偏向基因表达的进化之间的关系，该相关性捕获了两性基因如何独立调节。使用来自果蝇的转录组数据，我们发现大多数基因都具有较高的 r(MF)，并且目前暴露于性对抗选择的基因比其他基因具有更高的平均 r(MF)。我们进一步表明，在黑腹果蝇中，与具有低 r(MF) 的基因相比，具有高 r(MF) 的基因具有不太明显的性别偏见基因表达，并且黑腹果蝇中 r(MF) 的强度可以预测黑腹果蝇和果蝇属其他六个物种之间基因表达的性别偏见变化的程度。总之，我们的结果表明，共享基因组限制了性二态性的短期和长期进化。
Males and females share most of their genomes, and differences between the sexes can therefore not evolve through sequence divergence in protein coding genes. Sexual dimorphism is instead restricted to occur through sex-specific expression and splicing of gene products. Evolution of sexual dimorphism through these mechanisms should, however, also be constrained when the sexes share the genetic architecture for regulation of gene expression. Despite these obstacles, sexual dimorphism is prevalent in the animal kingdom and commonly evolves rapidly. Here, we ask whether the genetic architecture of gene expression is plastic and easily molded by sex-specific selection, or if sexual dimorphism evolves rapidly despite pervasive genetic constraint. To address this question, we explore the relationship between the intersexual genetic correlation for gene expression (r(MF)), which captures how independently genes are regulated in the sexes, and the evolution of sex-biased gene expression. Using transcriptome data from Drosophila melanogaster, we find that most genes have a high r(MF) and that genes currently exposed to sexually antagonistic selection have a higher average r(MF) than other genes. We further show that genes with a high r(MF) have less pronounced sex-biased gene expression than genes with a low r(MF) within D. melanogaster and that the strength of the r(MF) in D. melanogaster predicts the degree to which the sex bias of a gene's expression has changed between D. melanogaster and six other species in the Drosophila genus. In sum, our results show that a shared genome constrains both short- and long-term evolution of sexual dimorphism.