title: The mitochondrial genome of Parascaris univalens--implications for a "forgotten" parasite.
abstract: BACKGROUND
  Parascaris univalens is an ascaridoid nematode of equids. Little is known about its epidemiology and population genetics in domestic and wild horse populations. PCR-based methods are suited to support studies in these areas, provided that reliable genetic markers are used. Recent studies have shown that mitochondrial (mt) genomic markers are applicable in such methods, but no such markers have been defined for P. univalens.
  
  
  METHODS
  Mt genome regions were amplified from total genomic DNA isolated from P. univalens eggs by long-PCR and sequenced using Illumina technology. The mt genome was assembled and annotated using an established bioinformatic pipeline. Amino acid sequences inferred from all protein-encoding genes of the mt genomes were compared with those from other ascaridoid nematodes, and concatenated sequences were subjected to phylogenetic analysis by Bayesian inference.
  
  
  RESULTS
  The circular mt genome was 13,920 bp in length and contained two ribosomal RNA, 12 protein-coding and 22 transfer RNA genes, consistent with those of other ascaridoids. Phylogenetic analysis of the concatenated amino acid sequence data for the 12 mt proteins showed that P. univalens was most closely related to Ascaris lumbricoides and A. suum, to the exclusion of other ascaridoids.
  
  
  CONCLUSIONS
  This mt genome representing P. univalens now provides a rich source of genetic markers for future studies of the genetics and epidemiology of this parasite and its congener, P. equorum. This focus is significant, given that there is no published information on the specific prevalence and distribution of P. univalens infection in domestic and wild horse populations.
authors.affiliation: Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Melbourne, Victoria, Australia. jabbara@unimelb.edu.au.
authors.forename: Abdul
authors.initials: A
authors.lastname: Jabbar
authors.forename: D Timothy J
authors.initials: DT
authors.lastname: Littlewood
authors.forename: Namitha
authors.initials: N
authors.lastname: Mohandas
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Briscoe
authors.forename: Peter G
authors.initials: PG
authors.lastname: Foster
authors.forename: Fritz
authors.initials: F
authors.lastname: Müller
authors.forename: Georg
authors.initials: G
authors.lastname: von Samson-Himmelstjerna
authors.forename: Aaron R
authors.initials: AR
authors.lastname: Jex
authors.forename: Robin B
authors.initials: RB
authors.lastname: Gasser
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001199:Ascaridoidea / Q000235:genetics*; D018509:DNA, Helminth / Q000235:genetics*; D054629:Genome, Mitochondrial / Q000235:genetics*; D010802:Phylogeny
chemical_list: D018509:DNA, Helminth