School of Biological, Earth and Environmental Sciences, University College Cork, Cork, Ireland.
Environmental Research Institute, University College Cork, Cork, Ireland.
Front Immunol. 2021 Feb 26;12:568729. doi: 10.3389/fimmu.2021.568729. eCollection 2021.
Vertebrates have evolved a complex immune system required for the identification of and coordinated response to harmful pathogens. Migratory species spend periods of their life-cycle in more than one environment, and their immune system consequently faces a greater diversity of pathogens residing in different environments. In facultatively anadromous salmonids, individuals may spend parts of their life-cycle in freshwater and marine environments. For species such as the brown trout , sexes differ in their life-histories with females more likely to migrate to sea while males are more likely to stay and complete their life-cycle in their natal river. Salmonids have also undergone a lineage-specific whole genome duplication event, which may provide novel immune innovations but our current understanding of the differences in salmonid immune expression between the sexes is limited. We characterized the brown trout immune gene repertoire, identifying a number of canonical immune genes in non-salmonid teleosts to be duplicated in , with genes involved in innate and adaptive immunity. Through genome-wide transcriptional profiling ("RNA-seq") of male and female livers to investigate sex differences in gene expression amplitude and alternative splicing, we identified immune genes as being generally male-biased in expression. Our study provides important insights into the evolutionary consequences of whole genome duplication events on the salmonid immune gene repertoire and how the sexes differ in constitutive immune expression.
脊椎动物进化出了一套复杂的免疫系统，这套系统用于识别和协调对有害病原体的反应。洄游物种在其生命周期的某个阶段会在多个环境中度过，因此它们的免疫系统会面临更多栖息在不同环境中的病原体的多样性。在兼性洄游的鲑鱼中，个体的生命周期可能会在淡水和海洋环境中度过。对于像褐鳟这样的物种，雌性和雄性的生活史不同，雌性更有可能洄游到海洋，而雄性则更有可能留在出生的河流中完成它们的生命周期。鲑鱼也经历了一个特定于谱系的全基因组复制事件，这可能提供了新的免疫创新，但我们目前对鲑鱼性别间免疫表达差异的理解是有限的。我们对褐鳟的免疫基因库进行了特征描述，发现了一些非鲑鱼硬骨鱼中的经典免疫基因在其中发生了复制，这些基因涉及先天免疫和适应性免疫。通过对雄性和雌性肝脏进行全基因组转录谱分析（“RNA-seq”），以研究基因表达幅度和选择性剪接的性别差异，我们发现免疫基因的表达通常偏向雄性。我们的研究为鲑鱼免疫基因库的全基因组复制事件的进化后果以及性别间固有免疫表达的差异提供了重要的见解。
