Xie Chen, Künzel Sven, Tautz Diethard
Max Planck Institute for Evolutionary Biology, Plön, Germany.
Biomedical Pioneering Innovation Center, Peking University, Beijing, China.
Elife. 2025 Sep 17;13:RP99602. doi: 10.7554/eLife.99602.
Sexual dimorphism in phenotypes is largely driven by genes with sex-biased expression, spanning from key regulators to numerous organ-specific effectors. Current understanding is limited regarding the evolutionary dynamics of these genes in somatic tissues that generate the adult phenotype versus gonadal organs that are required for reproduction. Here, we investigate sex-biased gene expression and micro-evolutionary patterns of these genes in populations of subspecies and species of wild mice (genus ) that were raised under controlled conditions. We find a faster evolutionary turnover of sex-biased gene expression in somatic tissues, but not in the gonads, when compared to the turnover of non-sex-biased genes. We introduce a sex-biased gene expression index (SBI) to quantify individual variances. We find a range from binary to overlapping SBI patterns across individuals. SBI values do not correlate between organs of the same individuals, thus supporting a mosaic model of somatic sex determination. Comparison with data from humans shows mostly fewer sex-biased genes compared to mice and strongly overlapping SBI distributions between the somatic organs of the sexes. We conclude that adult individuals are composed of a mosaic spectrum of sex characteristics in their somatic tissues that should not be cumulated into a simple binary classification.
表型中的性别二态性很大程度上由具有性别偏向表达的基因驱动，从关键调节因子到众多器官特异性效应器。目前对于这些基因在产生成体表型的体细胞组织与生殖所需的性腺器官中的进化动态的理解有限。在此，我们研究了在受控条件下饲养的野生小鼠（属）亚种和物种群体中这些基因的性别偏向基因表达和微进化模式。我们发现，与非性别偏向基因的周转率相比，体细胞组织中性别偏向基因表达的进化周转率更快，而在性腺中则不然。我们引入了一个性别偏向基因表达指数（SBI）来量化个体差异。我们发现个体之间的SBI模式从二元到重叠不等。同一个体的不同器官之间SBI值不相关，因此支持体细胞性别决定的镶嵌模型。与人类数据的比较表明，与小鼠相比，性别偏向基因大多更少，并且两性体细胞器官之间的SBI分布有强烈重叠。我们得出结论，成年个体的体细胞组织由一系列性别特征的镶嵌谱组成，不应累积为简单的二元分类。
