The strength and form of natural selection on transcript abundance in the wild

Gene transcription variation is known to contribute to disease susceptibility and adaptation, but we currently know very little about how contemporary natural selection shapes transcript abundance. Here, we propose a novel analytical framework to quantify the strength and form of ongoing natural selection at the transcriptome level in a wild vertebrate. We estimated selection on transcript abundance in a cohort of a wild salmonid fish (Salmo trutta) affected by an extracellular myxozoan parasite (Tetracapsuloides bryosalmonae) through mark-recapture field sampling and the integration of RNA-seq with classical regression-based selection analysis. We show, based on fin transcriptomes of the host, that infection by the parasite and subsequent host survival is linked to upregulation of mitotic cell cycle process. We also detect a widespread signal of disruptive selection on transcripts linked to host immune defence, host-pathogen interactions, cellular repair and maintenance. Our results pr...

基因转录变异已知会影响疾病易感性与适应性，但目前我们对当代自然选择如何塑造转录本丰度（transcript abundance）知之甚少。在此，我们提出一种新型分析框架，用于量化野生脊椎动物转录组（transcriptome）水平上正在进行的自然选择的强度与形式。我们通过标记重捕野外采样，并整合RNA测序（RNA-seq）与经典回归选择分析（regression-based selection analysis），对受胞外粘体动物寄生虫（四囊虫，Tetracapsuloides bryosalmonae）影响的野生鲑科鱼类（褐鳟，Salmo trutta）群体的转录本丰度选择进行了估算。基于宿主的鳍转录组，我们发现寄生虫感染及后续宿主存活与有丝分裂细胞周期过程（mitotic cell cycle process）的上调相关。我们还检测到，在与宿主免疫防御、宿主-病原体互作及细胞修复与维持相关的转录本上，存在广泛的分裂选择（disruptive selection）信号。我们的结果显...