Characterization of the transcriptome, nucleotide sequence polymorphism, and natural selection in the desert adapted mouse Peromyscus eremicus

As a direct result of intense heat and aridity, deserts are thought to be among the most harsh of environments, particularly for their mammalian inhabitants. Given that osmoregulation can be challenging for these animals, with failure resulting in death, strong selection should be observed on genes related to the maintenance of water and solute balance. One such animal, Peromyscus eremicus, is native to the desert regions of the southwest United States and may live its entire life without oral fluid intake. As a first step toward understanding the genetics that underlie this phenotype, we present a characterization of the P. eremicus transcriptome. We assay four tissues (kidney, liver, brain, testes) from a single individual and supplement this with population level renal transcriptome sequencing from 15 additional animals. We identified a set of transcripts undergoing both purifying and balancing selection based on estimates of Tajima’s D. In addition, we used the branch-site test to i...

由于极端高温与干旱的直接作用，荒漠被公认为全球环境最为严苛的生境之一，对栖息其中的哺乳动物而言尤为如此。鉴于渗透压调节（osmoregulation）对这类动物极具挑战性，一旦调节失衡便会引发死亡，因此与水分及溶质平衡维持相关的基因势必会受到强烈的选择压力。其中代表性物种为荒漠鹿鼠（Peromyscus eremicus），它们原产于美国西南部荒漠区域，甚至可在终生不通过口腔摄入液体的情况下完成整个生命周期。为解析该特殊表型背后的遗传基础，本研究首次对荒漠鹿鼠的转录组（transcriptome）进行了系统性表征。我们对单只个体的四种组织（肾脏、肝脏、大脑、睾丸）开展了转录组测序分析，并补充了另外15只个体的群体水平肾脏转录组测序数据。基于Tajima's D检验的评估结果，我们鉴定出了一组同时受到净化选择与平衡选择作用的转录本。此外，我们还使用分支位点检验（branch-site test）对