Tu Feiyun, Qiao Yaqin, Zhao Wenjing, Wu Tong
Ministry of Education Key Laboratory for Ecology of Tropical Islands, Key Laboratory of Tropical Animal and Plant Ecology of Hainan Province, College of Life Sciences, Hainan Normal University, Haikou, China.
Mitochondrial DNA A DNA Mapp Seq Anal. 2025 Apr-May;35(3-4):75-83. doi: 10.1080/24701394.2024.2416179. Epub 2024 Oct 17.
Different animal groups with varying locomotion modes may have unique energy requirements. Mitochondria produce adenosine triphosphate (ATP) and reactive oxygen species via oxidative phosphorylation to support organisms energy requirements. The tribes Pteromyini (flying squirrels) and Sciurini (tree squirrels), two closely related taxa within the family Sciuridae, exhibit distinct locomotion modes, energy requirements, and likely face different selective pressures on mitochondrial protein-coding genes (PCGs). We analysed 13 mitochondrial genome sequences from species belonging to the tribe Pteromyini and 117 from species belonging to the tribe Sciurini. Phylogenetic analysis revealed Pteromyini and Sciurini formed a sister relationship within the family Sciuridae. Among the 13 PCGs, exhibited the highest dN/dS values, while showed the lowest. The background selection ratio (ω) values for six genes (, , , , , and ) in Pteromyini were lower than the foreground selection ratio (ω) values observed in Sciurini. A RELAX analysis revealed that , , , and genes experienced intensified in selection strength. BUSTED analysis identified stronger signatures of diversifying selection in and , highlighting amino acid changes. MEME identified episodic diversifying selection at specific sites among eight PCGs. These findings revealed distinct selective pressures on PCGs in flying and tree squirrels.
不同运动模式的动物群体可能有独特的能量需求。线粒体通过氧化磷酸化产生三磷酸腺苷（ATP）和活性氧，以满足生物体的能量需求。鼯鼠族（鼯鼠）和松鼠族（树松鼠）是松鼠科中两个密切相关的分类群，它们表现出不同的运动模式、能量需求，并且可能在 mitochondrial protein-coding genes (PCGs) 上面临不同的选择压力。我们分析了来自鼯鼠族物种的13个线粒体基因组序列和来自松鼠族物种的117个线粒体基因组序列。系统发育分析表明，鼯鼠族和松鼠族在松鼠科中形成了姐妹关系。在13个PCGs中， 表现出最高的dN/dS值，而 显示出最低的dN/dS值。鼯鼠族中六个基因（ 、 、 、 、 和 ）的背景选择率（ω）值低于松鼠族中观察到的前景选择率（ω）值。RELAX分析表明， 、 、 和 基因的选择强度增强。BUSTED分析确定了 和 中更强的多样化选择特征，突出了氨基酸变化。MEME在八个PCGs的特定位点识别出间歇性多样化选择。这些发现揭示了鼯鼠和树松鼠PCGs上不同的选择压力。
