Duan D-Y, Chen Z, Fu Y-T, Liu G-H, Cheng T-Y
Hunan Provincial Key Laboratory of Protein Engineering in Animal Vaccines, College of Veterinary Medicine, Hunan Agricultural University, Changsha, Hunan Province, China.
Hunan Co-Innovation Center of Animal Production Safety, College of Veterinary Medicine, Hunan Agricultural University, Changsha, Hunan Province, China.
Med Vet Entomol. 2021 Sep;35(3):513-522. doi: 10.1111/mve.12523. Epub 2021 Apr 30.
In this study, the authors sequenced and characterized the complete mitochondrial (mt) genomes of two hard ticks of the genus Ixodes, I. nipponensis and Ixodes (Pholeoixodes) sp., which were 14 505 and 14 543 bp in length, respectively. Their mt genomes encoded 37 genes, including 13 protein-coding genes (PCGs), 22 transfer RNA genes and two ribosomal RNA genes, and have only one non-coding region. The gene order in their mt genomes was the same as that of other Ixodes spp. mt genomes. The average sequence identity, combined nucleotide diversity, non-synonymous/synonymous substitutions ratio analyses consistently demonstrated that cox1, rrnS, cox2, cox3 and cytb were the most conserved and atp8, nad6 and nad2 were the most variable genes across Ixodes mitogenomes. Phylogeny of the present Ixodes spp., and other selected hard tick species, based on concatenated amino acid sequences of PCGs, confirmed their position within the genus Ixodes and sub-family Ixodinae. The novel mt markers described herein will be useful for further studies of the population genetics, molecular epidemiology and systematics of hard ticks.
在本研究中，作者对日本硬蜱（Ixodes nipponensis）和硬蜱属（Pholeoixodes）的一个种（Ixodes (Pholeoixodes) sp.）这两种硬蜱的完整线粒体（mt）基因组进行了测序和特征分析，其长度分别为14505和14543 bp。它们的线粒体基因组编码37个基因，包括13个蛋白质编码基因（PCGs）、22个转运RNA基因和两个核糖体RNA基因，且只有一个非编码区。它们线粒体基因组中的基因排列顺序与其他硬蜱属物种的线粒体基因组相同。平均序列同一性、联合核苷酸多样性、非同义/同义替换率分析一致表明，细胞色素c氧化酶亚基1（cox1）、小核糖体亚基RNA（rrnS）、细胞色素c氧化酶亚基2（cox2）、细胞色素c氧化酶亚基3（cox3）和细胞色素b（cytb）是硬蜱线粒体基因组中最保守的基因，而ATP合酶亚基8（atp8）、烟酰胺腺嘌呤二核苷酸脱氢酶亚基6（nad6）和烟酰胺腺嘌呤二核苷酸脱氢酶亚基2（nad2）是最可变基因。基于蛋白质编码基因的串联氨基酸序列对当前硬蜱属物种以及其他选定的硬蜱物种进行系统发育分析，证实了它们在硬蜱属和硬蜱亚科中的位置。本文描述的新型线粒体标记物将有助于进一步研究硬蜱的群体遗传学、分子流行病学和系统学。
