Li Qianqian, Chen Wenli, Mao Xiuguang
School of Ecological and Environmental Sciences, Institute of Eco-Chongming (IEC) East China Normal University Shanghai China.
Ecol Evol. 2022 Jun 22;12(6):e9025. doi: 10.1002/ece3.9025. eCollection 2022 Jul.
MicroRNAs (miRNAs) are important post-transcriptional regulators of gene expression and play key roles in many biological processes, such as development and response to multiple stresses. However, little is known about their roles in generating novel phenotypes and phenotypic variation during the course of animal evolution. Here, we, for the first time, characterized the miRNAs of the cochlea in an echolocating bat (). We sampled eight individuals from two subspecies with significant echolocation call frequency differences. We identified 365 miRNAs and 121 of them were novel. By searching sequences of these miRNAs precursors in multiple high-quality mammal genomes, we found one specific miRNA shared by all echolocating bats but not present in all other nonecholocating mammals. The targeted genes of this miRNA included several known hearing genes (e.g., and ). Together with the matched mRNA-seq data, we identified 1766 differentially expressed genes (DEGs) between the two subspecies and 555 of them were negatively regulated by differentially expressed miRNAs (DEMs). We found that almost half of known hearing genes in the list of all DEGs were regulated negatively by DEMs, suggesting an important role of miRNAs in call frequency variation of the two subspecies. These targeted DEGs included several important hearing genes (e.g., , and ) that have been shown to be important in ultrasonic hearing of echolocating mammals.
微小RNA（miRNA）是基因表达重要的转录后调节因子，在许多生物学过程中发挥关键作用，如发育以及对多种应激的反应。然而，关于它们在动物进化过程中产生新表型和表型变异方面的作用，我们知之甚少。在此，我们首次对一种回声定位蝙蝠的耳蜗miRNA进行了表征。我们从两个回声定位叫声频率存在显著差异的亚种中采集了8个个体的样本。我们鉴定出365个miRNA，其中121个是新发现的。通过在多个高质量哺乳动物基因组中搜索这些miRNA前体的序列，我们发现了一种所有回声定位蝙蝠共有的特定miRNA，但在所有其他非回声定位哺乳动物中不存在。这种miRNA的靶基因包括几个已知的听力相关基因（如 和 ）。结合匹配的mRNA测序数据，我们在两个亚种之间鉴定出1766个差异表达基因（DEG），其中555个受到差异表达miRNA（DEM）的负调控。我们发现，在所有DEG列表中，几乎一半的已知听力相关基因受到DEM的负调控，这表明miRNA在两个亚种的叫声频率变异中起重要作用。这些靶向的DEG包括几个重要的听力相关基因（如 、 和 ），这些基因已被证明在回声定位哺乳动物的超声听力中很重要。
