He Yanxia, Xiang Shifei, Luo Hongbin, Chen Dali, Guo Xianguang
Medical School, Hubei Minzu University, Enshi, 445000, China.
Enshi Huiyi Hospital of Rheumatic Diseases, Enshi, 445000, China.
Genetica. 2025 May 17;153(1):20. doi: 10.1007/s10709-025-00237-4.
Black flies (family Simuliidae) are globally distributed insects of great medical and veterinary importance. However, little is known about their mitogenomics. Therefore, in this study, the mitochondrial genomes (mitogenomes) of five black fly species‒Simulium bidentatum, S. siripoomense, S. fenestratum, S. chamlongi, S. quinquestriatum‒were sequenced using next-generation sequencing. We conducted a comprehensive comparative analysis of these mitogenomes focusing on sequence length, A + T content, A/T bias, A + T- rich regions, overlapping and intergenic regions, nucleotide composition, relative synonymous codon usage, and the non-synonymous/synonymous substitution ratio (Ka/Ks). Additionally, we analyzed the phylogenetic implications in combination with the Simuliidae and Nematocera species available in GenBank. The mitogenomes ranged from 15,739 to 16,451 base pairs (bp); each contained 37 genes, with no gene rearrangements. The tRNA (Ser1) lacks the dihydrouridine arm. Selection pressure analysis of 13 PCGs in 45 Nematocera mitogenomes revealed that nd2, nd5, nd4 l, and nd1 had Ka/Ks ratios greater than 1, indicating higher rates of non-synonymous substitutions. In contrast, cox1 showed the lowest Ka/Ks values, indicating strong purifying selection. Phylogenetic analyses supported the monophyly of each subgenus within Simulium, but revealed different subgeneric relationships compared to previous studies. We also observed that different samples can yield different phylogenetic results for higher level relationships within Culicomorpha. The phylogenetic position of Anisopodidae within the Bibionomorpha remains unclear and warrants further investigation.
蚋（蚋科）是全球分布的昆虫，具有重大的医学和兽医学意义。然而，关于它们的线粒体基因组学却知之甚少。因此，在本研究中，我们使用下一代测序技术对五种蚋——双齿蚋、西里布姆蚋、窗蚋、占隆蚋、五纹蚋——的线粒体基因组（线粒体基因组）进行了测序。我们对这些线粒体基因组进行了全面的比较分析，重点关注序列长度、A+T含量、A/T偏差、富含A+T的区域、重叠和基因间隔区域、核苷酸组成、相对同义密码子使用情况以及非同义/同义替换率（Ka/Ks）。此外，我们结合GenBank中可用的蚋科和长角亚目物种分析了系统发育意义。线粒体基因组长度在15,739至16,451碱基对（bp）之间；每个都包含37个基因，没有基因重排。tRNA（Ser1）缺少二氢尿嘧啶臂。对45个长角亚目线粒体基因组中13个蛋白质编码基因的选择压力分析表明，nd2、nd5、nd4l和nd1的Ka/Ks比率大于1，表明非同义替换率较高。相比之下，cox1显示出最低的Ka/Ks值，表明有强烈的纯化选择。系统发育分析支持蚋属内每个亚属的单系性，但与先前的研究相比，揭示了不同的亚属关系。我们还观察到，不同的样本对于库蚊亚科内更高层次的关系可能会产生不同的系统发育结果。大蚊亚目内扁角蚊科的系统发育位置仍不清楚，需要进一步研究。
