title: The complete mitochondrial genome of the gullet worm Gongylonema pulchrum: gene content, arrangement, composition and phylogenetic implications.
abstract: BACKGROUND
  Gongylonema pulchrum (Nematoda: Gongylonematidae), a thread-like spirurid gullet worm, infects a range of mammalian definitive hosts, including cattle, pigs, equines, goats, primates and humans, and can cause gongylonemiasis.
  
  
  METHODS
  In the present study, the complete mitochondrial (mt) genome of G. pulchrum was obtained using Long-range PCR and subsequent primer walking. The phylogenetic position of G. pulchrum within the Spiruromorpha was established using Bayesian analyses of the protein-coding genes at the amino acid level.
  
  
  RESULTS
  The length of this AT-rich (75.94%) mt genome is 13,798 bp. It contains 12 protein-coding genes, two ribosomal RNA genes, 22 transfer RNA genes and one non-coding region. The gene arrangement is the same as those of Thelazia callipaeda (Thelaziidae) and Setaria digitata (Onchocercidae), but distinct from that of Heliconema longissimum (Physalopteridae). Phylogenetic analyses, based on the concatenated amino acid sequence data for all 12 protein-coding genes using Bayesian inference (BI) method, showed that G. pulchrum (Gongylonematidae) was more closely related to Spirocerca lupi (Spiruroidea) than other members of the infraorder Spiruromorpha.
  
  
  CONCLUSIONS
  The present study represents the first mt genome sequence for the family Gongylonematidae, which provides the opportunity to develop novel genetic markers for studies of epidemiology, population genetics and systematics of this nematode of human and animal health significance.
authors.affiliation: 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, Peoples Republic of China. liuguohua5202008@163.com.
authors.forename: Guo-Hua
authors.initials: GH
authors.lastname: Liu
authors.affiliation: College of Veterinary Medicine, Northwest A&F University, Shaanxi Province, Yangling, 712100, Peoples Republic of China. yqjia1987@163.com.
authors.forename: Yan-Qing
authors.initials: YQ
authors.lastname: Jia
authors.affiliation: College of Veterinary Medicine, Northwest A&F University, Shaanxi Province, Yangling, 712100, Peoples Republic of China. 422765109@qq.com.
authors.forename: Ya-Nan
authors.initials: YN
authors.lastname: Wang
authors.affiliation: College of Veterinary Medicine, Northwest A&F University, Shaanxi Province, Yangling, 712100, Peoples Republic of China. zgh083@nwsuaf.edu.cn.
authors.forename: Guang-Hui
authors.initials: GH
authors.lastname: Zhao
authors.affiliation: 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, Peoples Republic of China. xingquanzhu1@hotmail.com.
authors.forename: Xing-Quan
authors.initials: XQ
authors.lastname: Zhu
mesh_terms: D000818:Animals; D004272:DNA, Mitochondrial / Q000737:chemistry* / Q000235:genetics*; D054629:Genome, Mitochondrial; D006376:Helminths; D024101:Mitochondrial Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013151:Spiruroidea / Q000235:genetics*
chemical_list: D004272:DNA, Mitochondrial; D024101:Mitochondrial Proteins