School of Life Sciences, Zhengzhou University, No.100 Science Avenue, Zhengzhou, Henan Province 450001, PR China.
Institute of Forensic Science, Ministry of Public Security, No.17, South Muxidi Lane, Xicheng District, Beijing 100038, PR China.
Int J Biol Macromol. 2018 Oct 15;118(Pt B):1400-1405. doi: 10.1016/j.ijbiomac.2018.06.133. Epub 2018 Jun 27.
There is considerable interest in examining how circadian rhythms function and evolve in subterranean rodents that spend its entire life in underground, darkness environments. Here, we investigated the evolution of PER and CRY genes that are important for mammalian biological clocks in the subterranean rodents. We performed phylogenetic analyses using newly sequenced PER and CRY from the subterranean rodent Lasiopodomys mandarinus, the related aboveground rodent Lasiopodomys brandtii, sequences from other rodents available in public databases. The constructed phylogenetic tree revealed no convergence among subterranean rodents. Phylogenetic and selection-pressure analyses revealed the effect of purifying selection (ω < 1) on PER and CRY in subterranean rodents. Additionally, evidence of positive selection on the CRY1 and PER3 genes in several subterranean rodent species suggests adaptations to a dark habitat. Most of the positively selected sites in CRY1 and PER3 were on the C-terminus. Our findings suggest that PER and CRY are highly conserved during evolution as subterranean rodents adapted to the darkness environment, and that the C-terminal domain of CRY1 and PER3 may be the core regulatory structure of circadian rhythms. The study advances our understanding of how major circadian genes evolved in subterranean rodents.
人们对于研究地下洞穴环境中生活的地下啮齿动物的昼夜节律如何运作和进化非常感兴趣。在这里，我们研究了 PER 和 CRY 基因在地下啮齿动物中的进化，这些基因对于哺乳动物的生物钟非常重要。我们使用新测序的地下啮齿动物中华鼢鼠（Lasiopodomys mandarinus）的 PER 和 CRY 序列，以及来自公共数据库中的其他啮齿动物的序列进行了系统发育分析。构建的系统发育树显示地下啮齿动物之间没有趋同进化。系统发育和选择压力分析表明，地下啮齿动物的 PER 和 CRY 受到纯化选择（ω < 1）的影响。此外，CRY1 和 PER3 基因在几种地下啮齿动物物种中存在正选择的证据表明，它们适应了黑暗的栖息地。CRY1 和 PER3 中的大多数正选择位点位于 C 末端。我们的研究结果表明，PER 和 CRY 在地下啮齿动物适应黑暗环境的过程中，在进化过程中高度保守，而 CRY1 和 PER3 的 C 末端结构域可能是昼夜节律的核心调节结构。这项研究增进了我们对主要的昼夜节律基因在地下啮齿动物中进化的理解。
