Characterisation of the mitochondrial genome and phylogenetic analysis of Toxocara apodemi (Nematoda: Ascarididae)

IF 16.4 1区化学 Q1 CHEMISTRY, MULTIDISCIPLINARY

Accounts of Chemical Research Pub Date : 2024-04-15 DOI:10.1017/s0022149x24000221

Y. Gao, Y. Hu, S. Xu, H. Liang, H. Lin, T. H. Yin, K. Zhao

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引用次数: 0

Abstract

We first sequenced and characterised the complete mitochondrial genome of Toxocara apodeme, then studied the evolutionary relationship of the species within Toxocaridae. The complete mitochondrial genome was amplified using PCR with 14 specific primers. The mitogenome length was 14303 bp in size, including 12 PCGs (encoding 3,423 amino acids), 22 tRNAs, 2 rRNAs, and 2 NCRs, with 68.38% A+T contents. The mt genomes of T. apodemi had relatively compact structures with 11 intergenic spacers and 5 overlaps. Comparative analyses of the nucleotide sequences of complete mt genomes showed that T. apodemi had higher identities with T. canis than other congeners. A sliding window analysis of 12 PCGs among 5 Toxocara species indicated that nad4 had the highest sequence divergence, and cox1 was the least variable gene. Relative synonymous codon usage showed that UUG, ACU, CCU, CGU, and UCU most frequently occurred in the complete genomes of T. apodemi. The Ka/Ks ratio showed that all Toxocara mt genes were subject to purification selection. The largest genetic distance between T. apodemi and the other 4 congeneric species was found in nad2, and the smallest was found in cox2. Phylogenetic analyses based on the concatenated amino acid sequences of 12 PCGs demonstrated that T. apodemi formed a distinct branch and was always a sister taxon to other congeneric species. The present study determined the complete mt genome sequences of T. apodemi, which provide novel genetic markers for further studies of the taxonomy, population genetics, and systematics of the Toxocaridae nematodes.

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Toxocara apodemi（线虫纲：蛔虫科）线粒体基因组的特征和系统发育分析

我们首先对尾柄弓形虫（Toxocara apodeme）的完整线粒体基因组进行了测序和鉴定，然后研究了该物种在弓形虫科（Toxocaridae）中的进化关系。完整的线粒体基因组是用 14 种特异引物进行 PCR 扩增的。线粒体基因组长度为 14303 bp，包括 12 个 PCGs（编码 3423 个氨基酸）、22 个 tRNAs、2 个 rRNAs 和 2 个 NCRs，A+T 含量为 68.38%。T.apodemi的mt基因组结构相对紧凑，有11个基因间距和5个重叠。完整 mt 基因组核苷酸序列的比较分析表明，T. apodemi 与 T. canis 的同源性高于其他同源种。对 5 个弓形虫物种的 12 个 PCGs 进行的滑动窗口分析表明，nad4 的序列差异最大，而 cox1 是可变性最小的基因。同义密码子相对使用率显示，UUG、ACU、CCU、CGU 和 UCU 在阿波德米弓形虫的完整基因组中出现频率最高。Ka/Ks 比率表明，所有弓形虫的 mt 基因都受到了纯化选择的影响。apodemi与其他4个同源种之间最大的遗传距离出现在nad2中，最小的遗传距离出现在cox2中。基于 12 个 PCGs 氨基酸序列的系统发育分析表明，T. apodemi 形成了一个独特的分支，并且始终是其他同源种的姊妹类群。本研究确定了阿朴线虫的完整 mt 基因组序列，为进一步研究毒蛾科线虫的分类学、种群遗传学和系统学提供了新的遗传标记。

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来源期刊

Accounts of Chemical Research 化学-化学综合

CiteScore

31.40

自引率

1.10%

发文量

312

审稿时长

2 months

期刊介绍： Accounts of Chemical Research presents short, concise and critical articles offering easy-to-read overviews of basic research and applications in all areas of chemistry and biochemistry. These short reviews focus on research from the author’s own laboratory and are designed to teach the reader about a research project. In addition, Accounts of Chemical Research publishes commentaries that give an informed opinion on a current research problem. Special Issues online are devoted to a single topic of unusual activity and significance. Accounts of Chemical Research replaces the traditional article abstract with an article "Conspectus." These entries synopsize the research affording the reader a closer look at the content and significance of an article. Through this provision of a more detailed description of the article contents, the Conspectus enhances the article's discoverability by search engines and the exposure for the research.