College of Animal Science and Technology, Anhui Agricultural University, Hefei, Anhui Province, 230036, People's Republic of China.
State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province, 730046, People's Republic of China.
Parasitol Res. 2021 May;120(5):1677-1686. doi: 10.1007/s00436-021-07069-z. Epub 2021 Mar 23.
Different species of the genus Ophidascaris (Baylis, 1921; Nematoda: Ascaridida, Ascaridoidea) are intestinal parasites of various snake species. More than 30 Ophidascaris species have been reported worldwide; however, few molecular genetic studies have been conducted on this genus. We sequenced the complete mitogenome of Ophidascaris wangi parasitizing two snake species of the family Colubridae, i.e., Elaphe carinata (Günther, 1864) and Dinodon rufozonatum. The mitogenome sequence of O. wangi was approximately 14,660 base pairs (bp) long and encoded 36 genes, including 12 protein-coding genes (PCGs), 2 ribosomal RNA (rRNA) genes, and 22 transfer RNA genes. Gene arrangement, genome content, and transcription direction were in line with those in Toxascaris leonina (Linstow, 1902; Ascaridida: Ascarididae). Phylogenetics of O. wangi and other ascaridoids were reconstructed based on the concatenated amino acid sequences of 12 PCGs, and on nucleotide sequences of 12 PCGs and two rRNA genes. Phylogenetic analyses were performed using maximum likelihood and Bayesian inference methods, and the results suggested that O. wangi constitutes a sister clade of Ascaris, Parascaris, Baylisascaris, and Toxascaris within the family Ascarididae, which is a sister clade of Toxocaridae. The mitogenome sequence of O. wangi obtained from the present study will be useful for future identification of the nematode worms in the genus Ophidascaris and will increase the understanding of population genetics, molecular epidemiology, and phylogenetics of ascaridoid nematodes in snakes.
蛇蛔科（Baylis，1921；线虫纲：蛔目，蛔总科）的不同种 Ophidascaris 是各种蛇类的肠道寄生虫。全世界已经报道了超过 30 种 Ophidascaris 物种；然而，针对该属进行的分子遗传研究较少。我们对寄生在 Colubridae 科两种蛇类（Elaphe carinata（Günther，1864）和 Dinodon rufozonatum）中的 Ophidascaris wangi 的完整线粒体基因组进行了测序。O. wangi 的线粒体基因组序列约为 14660 个碱基对（bp）长，编码 36 个基因，包括 12 个蛋白编码基因（PCGs）、2 个核糖体 RNA（rRNA）基因和 22 个转移 RNA 基因。基因排列、基因组内容和转录方向与 Toxascaris leonina（Linstow，1902；蛔目：蛔科）一致。基于 12 个 PCGs 的氨基酸序列和 12 个 PCGs 和 2 个 rRNA 基因的核苷酸序列，重建了 O. wangi 和其他蛔总科的系统发育。使用最大似然法和贝叶斯推断法进行系统发育分析，结果表明 O. wangi 构成了蛔科中的 Ascaris、Parascaris、Baylisascaris 和 Toxascaris 的姐妹群，而蛔科又是 Toxocaridae 的姐妹群。本研究获得的 O. wangi 线粒体基因组序列将有助于今后鉴定蛇类 Ophidascaris 属的线虫，并增加对蛇类蛔总科线虫的种群遗传学、分子流行病学和系统发育的了解。
