Dean Rebecca, Mank Judith E
Am Nat. 2016 Sep;188(3):E74-84. doi: 10.1086/687526. Epub 2016 Jul 5.
Genetic correlations between males and females are often thought to constrain the evolution of sexual dimorphism. However, sexually dimorphic traits and the underlying sexually dimorphic gene expression patterns are often rapidly evolving. We explore this apparent paradox by measuring the genetic correlation in gene expression between males and females (Cmf) across broad evolutionary timescales, using two RNA-sequencing data sets spanning multiple populations and multiple species. We find that unbiased genes have higher Cmf than sex-biased genes, consistent with intersexual genetic correlations constraining the evolution of sexual dimorphism. However, we found that highly sex-biased genes (both male and female biased) also had higher tissue specificity, and unbiased genes had greater expression breadth, suggesting that pleiotropy may constrain the breakdown of intersexual genetic correlations. Finally, we show that genes with high Cmf showed some degree of sex-specific changes in gene expression in males and females. Together, our results suggest that genetic correlations between males and females may be less important in constraining the evolution of sex-biased gene expression than pleiotropy. Sex-specific regulatory variation and tissue specificity may resolve the paradox of widespread sex bias within a largely shared genome.
通常认为，雄性与雌性之间的遗传相关性会限制两性异形的进化。然而，两性异形的性状以及潜在的两性异形基因表达模式往往在快速进化。我们通过在广泛的进化时间尺度上测量雄性与雌性之间基因表达的遗传相关性（Cmf）来探究这一明显的矛盾，使用了跨越多个种群和多个物种的两个RNA测序数据集。我们发现，无偏向性基因的Cmf高于性别偏向性基因，这与两性间的遗传相关性限制两性异形的进化一致。然而，我们发现高度性别偏向性的基因（包括雄性偏向和雌性偏向）也具有更高的组织特异性，而无偏向性基因具有更广泛的表达范围，这表明基因多效性可能会限制两性间遗传相关性的瓦解。最后，我们表明具有高Cmf的基因在雄性和雌性中表现出一定程度的性别特异性基因表达变化。总之，我们的结果表明，在限制性别偏向性基因表达的进化方面，雄性与雌性之间的遗传相关性可能不如基因多效性重要。性别特异性调控变异和组织特异性可能会解决在很大程度上共享的基因组中广泛存在的性别偏向性这一矛盾。
