title: The mitochondrial genome of Baylisascaris procyonis.
abstract: BACKGROUND
  Baylisascaris procyonis (Nematoda: Ascaridida), an intestinal nematode of raccoons, is emerging as an important helminthic zoonosis due to serious or fatal larval migrans in animals and humans. Despite its significant veterinary and public health impact, the epidemiology, molecular ecology and population genetics of this parasite remain largely unexplored. Mitochondrial (mt) genomes can provide a foundation for investigations in these areas and assist in the diagnosis and control of B. procyonis. In this study, the first complete mt genome sequence of B. procyonis was determined using a polymerase chain reaction (PCR)-based primer-walking strategy.
  
  
  RESULTS
  The circular mt genome (14781 bp) of B. procyonis contained 12 protein-coding, 22 transfer RNA and 2 ribosomal RNA genes congruent with other chromadorean nematodes. Interestingly, the B. procyonis mtDNA featured an extremely long AT-rich region (1375 bp) and a high number of intergenic spacers (17), making it unique compared with other secernentean nematodes characterized to date. Additionally, the entire genome displayed notable levels of AT skew and GC skew. Based on pairwise comparisons and sliding window analysis of mt genes among the available 11 Ascaridida mtDNAs, new primer pairs were designed to amplify specific short fragments of the genes cytb (548 bp fragment) and rrnL (200 bp fragment) in the B. procyonis mtDNA, and tested as possible alternatives to existing mt molecular beacons for Ascaridida. Finally, phylogenetic analysis of mtDNAs provided novel estimates of the interrelationships of Baylisasaris and Ascaridida.
  
  
  CONCLUSIONS
  The complete mt genome sequence of B. procyonis sequenced here should contribute to molecular diagnostic methods, epidemiological investigations and ecological studies of B. procyonis and other related ascaridoids. The information will be important in refining the phylogenetic relationships within the order Ascaridida and enriching the resource of markers for systematic, population genetic and evolutionary biological studies of parasitic nematodes of socio-economic importance.
authors: Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Ya'an, China.
authors: Yue
authors: Y
authors: Xie
authors: Zhihe
authors: Z
authors: Zhang
authors: Lili
authors: L
authors: Niu
authors: Qiang
authors: Q
authors: Wang
authors: Chengdong
authors: C
authors: Wang
authors: Jingchao
authors: J
authors: Lan
authors: Jiabo
authors: J
authors: Deng
authors: Yan
authors: Y
authors: Fu
authors: Huaming
authors: H
authors: Nie
authors: Ning
authors: N
authors: Yan
authors: Deying
authors: D
authors: Yang
authors: Guiying
authors: G
authors: Hao
authors: Xiaobin
authors: X
authors: Gu
authors: Shuxian
authors: S
authors: Wang
authors: Xuerong
authors: X
authors: Peng
authors: Guangyou
authors: G
authors: Yang
mesh_terms: D000818:Animals; D001199:Ascaridoidea / Q000235:genetics*; D017238:Genes, Helminth; D020459:Genes, rRNA; D054629:Genome, Mitochondrial; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000379:methods*; D012333:RNA, Messenger / Q000235:genetics; D012343:RNA, Transfer / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D012333:RNA, Messenger; D012343:RNA, Transfer