title: Mitochondrial genes and genomes support a cryptic species of tapeworm within Taenia taeniaeformis.
abstract: Taenia taeniaeformis is a globally distributed cestode, which uses felids as definitive and rodents as intermediate hosts. The complete mitochondrial DNA (mtDNA) of T. taeniaeformis from Germany (Tt-GER) was sequenced, and compared with that of another isolate from China (GenBank NC_014768; Tt-CHN), both taken from cats. Analysis of the two mtDNAs indicated that the isolates are significantly different from one another with 12.6% and 9.9% nucleotide and amino acid divergence between them, for concatenated protein-coding genes; overall difference based on a pairwise nucleotide alignment of complete mtDNAs was 11.8%. A phylogenetic analysis based on the 12 protein-coding genes of all available taeniid mtDNAs confirmed the two T. taeniaeformis isolates as sister taxa (likely separate species) and early divergent members of the genus, as suggested previously by morphology. Phylogenetic analysis of published fragments of mt genes rrnS, cox1 and nad1, which represent multiple geographic isolates of T. taeniaeformis also resolve two distinct clades that at present do not seem to be geographically isolated. Mean pairwise (nucleotide) differences between the two clades of T. taeniaeformis were approximately 11%, 10% and 13% in partial rrnS (182bp), cox1 (371bp) and nad1 (459bp) genes, respectively. Differences between entire mtDNAs and partial mt genes of the two T. taeniaeformis isolates are of a similar magnitude between established taeniid sister species. Tt-CHN differs from all other Taenia mtDNAs in lacking a short (∼69bp) non-coding region between trnY and trnL1. Partial mt fragment analysis highlighted likely misidentifications of T. taeniaeformis on GenBank.
authors.affiliation: Key Laboratory of Veterinary Parasitology of Gansu Province, Key Laboratory of Veterinary Public Health of Agriculture Ministry, State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730046, Gansu Province, PR China. jwanzhong@yahoo.com.cn
authors.forename: Wanzhong
authors.initials: W
authors.lastname: Jia
authors.forename: Hongbin
authors.initials: H
authors.lastname: Yan
authors.forename: Zhongzi
authors.initials: Z
authors.lastname: Lou
authors.forename: Xingwei
authors.initials: X
authors.lastname: Ni
authors.forename: Viktor
authors.initials: V
authors.lastname: Dyachenko
authors.forename: Hongmin
authors.initials: H
authors.lastname: Li
authors.forename: D Timothy J
authors.initials: DT
authors.lastname: Littlewood
mesh_terms: D000818:Animals; D002415:Cats; D002681:China; D016000:Cluster Analysis; D018509:DNA, Helminth / Q000737:chemistry / Q000235:genetics; D050259:Genes, Mitochondrial; D054629:Genome, Mitochondrial; D005858:Germany; D008969:Molecular Sequence Data; D010802:Phylogeny; D012377:Rodentia; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D013621:Taenia / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification
chemical_list: D018509:DNA, Helminth