Guo Dong-Hui, Zhang Yan, Fu Xue, Gao Yuan, Liu Yu-Ting, Qiu Jian-Hua, Chang Qiao-Cheng, Wang Chun-Ren
College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing, Heilongjiang 163319, PR China.
Exp Parasitol. 2016 Oct;169:22-7. doi: 10.1016/j.exppara.2016.07.004. Epub 2016 Jul 14.
Ticks are obligate blood-sucking ectoparasites of a wide range of vertebrates. They can transmit a range of pathogens that cause economic losses to livestock production as well as human disease. In the present study, the complete mitochondrial (mt) genome of Dermacentor silvarum was determined. The mt genome is 14,945 bp in length contains 37 genes, including 13 are protein-coding genes (cox1-3, nad1-6, nad4L, cytb, atp6 and atp8), two ribosomal RNA genes and 22 transfer RNA genes. The nucleotide composition of the D. silvarum mt genome was A + T biased at 78.78%; T was the most abundant nucleotide and G the least abundant. The mt genome of D. silvarum was 106 bp longer than that of Dermacentor nitens and the arrangements of two genomes were identical. For the 13 protein-coding genes, comparison between D. silvarum and D. nitens revealed sequence divergence at both the nucleotide (15.46-35.14%) and amino acid (6.05-48.98%) levels. Among them, cox1 was the most conserved gene, while atp8 was the least conserved. The lengths of the 13 protein-coding genes were the same or similar, except for cytb which was significantly longer in D. silvarum than in D. nitens. The mtDNA contained a variable repeat region consisting of a "similar to nad1" motif that was repeated three times, and the "Tick-box" motifs were also found. The overall difference between the nucleotide sequences of the two complete mt genomes was 21.4%. The mtDNA data presented in this study provide a rich resource for further studies on the phylogenetics, population genetics, and molecular epidemiology of ticks.
蜱是多种脊椎动物专性吸血的体外寄生虫。它们能传播一系列病原体，这些病原体可给家畜生产造成经济损失，还会引发人类疾病。在本研究中，测定了森林革蜱的完整线粒体（mt）基因组。该mt基因组长度为14,945 bp，包含37个基因，其中包括13个蛋白质编码基因（cox1 - 3、nad1 - 6、nad4L、cytb、atp6和atp8）、两个核糖体RNA基因和22个转运RNA基因。森林革蜱mt基因组的核苷酸组成中A + T含量偏高，为78.78%；T是含量最丰富的核苷酸，G是含量最少的核苷酸。森林革蜱的mt基因组比微小牛蜱的长106 bp，且两个基因组的排列相同。对于13个蛋白质编码基因，森林革蜱和微小牛蜱之间的比较显示，在核苷酸（15.46 - 35.14%）和氨基酸（6.05 - 48.98%）水平上均存在序列差异。其中，cox1是最保守的基因，而atp8是最不保守的基因。除cytb在森林革蜱中明显长于微小牛蜱外，13个蛋白质编码基因的长度相同或相似。该mtDNA包含一个可变重复区域，由一个重复三次的“类似于nad1”基序组成，并且还发现了“蜱盒”基序。两个完整mt基因组的核苷酸序列总体差异为21.4%。本研究中呈现的mtDNA数据为进一步研究蜱的系统发育学、群体遗传学和分子流行病学提供了丰富资源。
