title: The complete mitochondrial genome of Toxascaris leonina: Comparison with other closely related species and phylogenetic implications.
abstract: Adults of Toxascaris leonina (Nematoda: Ascarididae) live in the gastrointestinal tract of both dogs and cats, and cause significant economic losses and potential public health problem worldwide. Although many studies have given insights into this significant pathogen, to date, the complete mitochondrial (mt) genome sequence is still not available for T. leonina. Here, we sequenced the complete mt genome of T. leonina. This AT-rich (71.53%) mt genome (14,310bp) is circular and consists of 36 genes, including 12 genes for proteins, 2 genes for rRNA and 22 genes for tRNA. All mt genes of T. leonina are transcribed in the same direction. The gene order is the same as those of Ascaris spp. (Ascarididae), Toxocara spp. (Toxocaridae), Anisakis simplex and Contracaecum rudolphii B (Anisakidae), but distinct from that of Ascaridia spp. (Ascaridiidae). Phylogenetic analyses using concatenated amino acid sequences of 12 protein-coding genes by Bayesian inference (BI) showed distinct groups with high statistical support, and our data confirm that T. leonina is a member of the Ascarididae, and that this family is more closely related to the Toxocaridae rather than the Anisakidae within the Ascaridoidea. The determination of mt genome sequences of T. leonina provides novel genetic markers for studies into the systematics, population genetics and epidemiology of this parasite.
authors: 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, PR China; College of Veterinary Medicine, Hunan Agricultural University, Changsha, Hunan Province 410128, PR China.
authors: Guo-Hua
authors: GH
authors: Liu
authors: 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, PR China. Electronic address: zhoudonghui@caas.cn.
authors: Dong-Hui
authors: DH
authors: Zhou
authors: 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, PR China; College of Animal Science and Technology, Jilin Agriculture University, Changchun 130118, PR China.
authors: Lei
authors: L
authors: Zhao
authors: Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, PR China.
authors: Rong-Chuan
authors: RC
authors: Xiong
authors: 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, PR China; College of Veterinary Medicine, South China Agricultural University, Guangzhou, Guangdong Province 510642, PR China.
authors: Jian-Ying
authors: JY
authors: Liang
authors: 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, PR China; College of Veterinary Medicine, Hunan Agricultural University, Changsha, Hunan Province 410128, PR China; College of Animal Science and Technology, Jilin Agriculture University, Changchun 130118, PR China. Electronic address: xingquanzhu1@hotmail.com.
authors: Xing-Quan
authors: XQ
authors: Zhu
mesh_terms: D000818:Animals; D001499:Bayes Theorem; D002415:Cats; D004285:Dogs; D023061:Gene Order; D005819:Genetic Markers; D049751:Genome, Helminth; D054629:Genome, Mitochondrial; D007421:Intestine, Small / Q000469:parasitology; D010802:Phylogeny; D020539:Sequence Analysis, Protein; D017227:Toxascariasis / Q000469:parasitology / Q000662:veterinary*; D014114:Toxascaris / Q000145:classification* / Q000235:genetics*
chemical_list: D005819:Genetic Markers
keywords: Mitochondrial DNA; Mitochondrial genome; Phylogenetic analyses; Toxascaris leonina