Rayner Jack G, Hitchcock Thomas J, Bailey Nathan W
Centre for Biological Diversity, University of St Andrews, St Andrews KY16 9TH, UK.
Proc Biol Sci. 2021 Mar 31;288(1947):20210355. doi: 10.1098/rspb.2021.0355. Epub 2021 Mar 24.
Recent theory has suggested that dosage compensation mediates sexual antagonism over X-linked genes. This process relies on the assumption that dosage compensation scales phenotypic effects between the sexes, which is largely untested. We evaluated this by quantifying transcriptome variation associated with a recently arisen, male-beneficial, X-linked mutation across tissues of the field cricket , and testing the relationship between the completeness of dosage compensation and female phenotypic effects at the level of gene expression. Dosage compensation in was variable across tissues but usually incomplete, such that relative expression of X-linked genes was typically greater in females. Supporting the assumption that dosage compensation scales phenotypic effects between the sexes, we found tissues with incomplete dosage compensation tended to show female-skewed effects of the X-linked allele. In gonads, where expression of X-linked genes was most strongly female-biased, ovaries-limited genes were much more likely to be X-linked than were testes-limited genes, supporting the view that incomplete dosage compensation favours feminization of the X. Our results support the expectation that sex chromosome dosage compensation scales phenotypic effects of X-linked genes between sexes, substantiating a key assumption underlying the theoretical role of dosage compensation in determining the dynamics of sexual antagonism on the X.
近期理论表明,剂量补偿介导了X连锁基因上的性拮抗作用。这一过程依赖于剂量补偿在两性之间调节表型效应的假设,而这一假设在很大程度上尚未得到验证。我们通过量化与田间蟋蟀组织中一个最近出现的、对雄性有益的X连锁突变相关的转录组变异,并在基因表达水平上测试剂量补偿的完整性与雌性表型效应之间的关系,对这一假设进行了评估。蟋蟀的剂量补偿在不同组织中存在差异,但通常并不完全,因此X连锁基因在雌性中的相对表达通常更高。支持剂量补偿在两性之间调节表型效应这一假设的是,我们发现剂量补偿不完全的组织往往表现出X连锁等位基因对雌性的偏向效应。在性腺中,X连锁基因的表达在雌性中偏向性最强,卵巢特异性基因比睾丸特异性基因更有可能是X连锁的,这支持了不完全剂量补偿有利于X染色体雌性化的观点。我们的结果支持了性染色体剂量补偿在两性之间调节X连锁基因表型效应的预期,证实了剂量补偿在决定X染色体上性拮抗动态的理论作用背后的一个关键假设。