title: Ascaris phylogeny based on multiple whole mtDNA genomes.
abstract: Ascaris lumbricoides and A. suum are two parasitic nematodes infecting humans and pigs, respectively. There has been considerable debate as to whether Ascaris in the two hosts should be considered a single or two separate species. Previous studies identified at least three major clusters (A, B and C) of human and pig Ascaris based on partial cox1 sequences. In the present study, we selected major haplotypes from these different clusters to characterize their whole mitochondrial genomes for phylogenetic analysis. We also undertook coalescent simulations to investigate the evolutionary history of the different Ascaris haplotypes. The topology of the phylogenetic tree based on complete mitochondrial genomic sequences was found to be similar to partial cox1 sequencing, but the support at internal nodes was higher in the former. Coalescent simulations suggested the presence of at least two divergence events: the first one occurring early in the Neolithic period which resulted in a differentiated population of Ascaris in pigs (cluster C), the second occurring more recently (~900 generations ago), resulting in clusters A and B which might have been spread worldwide by human activities.
authors.affiliation: Department of Clinical Medicine, Health, Aarhus University, Denmark; Department of Veterinary Disease Biology, Faculty of Health Sciences, University of Copenhagen, Denmark. Electronic address: pn@clin.au.dk.
authors.forename: Peter
authors.initials: P
authors.lastname: Nejsum
authors.affiliation: Department of Genetics, Centre Hospitalier Universitaire Sainte-Justine Research Center, Montréal, Canada; Zoology Department, Faculty of Science, Cairo University, Giza, Egypt.
authors.forename: Mohamed B F
authors.initials: MB
authors.lastname: Hawash
authors.affiliation: School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom.
authors.forename: Martha
authors.initials: M
authors.lastname: Betson
authors.affiliation: Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom.
authors.forename: J Russell
authors.initials: JR
authors.lastname: Stothard
authors.affiliation: Department of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Victoria, Australia.
authors.forename: Robin B
authors.initials: RB
authors.lastname: Gasser
authors.affiliation: Department of Microbiology and Infection Control, Statens Serum Institut, Copenhagen, Denmark.
authors.forename: Lee O
authors.initials: LO
authors.lastname: Andersen
mesh_terms: D000818:Animals; D017164:Ascaris lumbricoides / Q000235:genetics*; D004272:DNA, Mitochondrial / Q000235:genetics; D003576:Electron Transport Complex IV / Q000235:genetics; D054629:Genome, Mitochondrial; D015801:Helminth Proteins / Q000235:genetics; D006801:Humans; D058885:Multilocus Sequence Typing; D010802:Phylogeny; D013552:Swine
chemical_list: D004272:DNA, Mitochondrial; D015801:Helminth Proteins; D003576:Electron Transport Complex IV
keywords: Ascaris; Human; Mitochondrial genomes; Phylogeny; Pig; Soil transmitted helminth