title: Microheterogeneity and coevolution: an examination of rDNA sequence characteristics in Neoparamoeba pemaquidensis and its prokinetoplastid endosymbiont.
abstract: Neoparamoeba pemaquidensis, the etiological agent of amoebic gill disease, has shown surprising sequence variability among different copies of the 18S ribosomal RNA gene within an isolate. This intra-genomic microheterogeneity was confirmed and extended to an analysis of the internal transcribed spacer (ITS) region. High levels of intra-genomic nucleotide diversity (Pi=0.0201-0.0313) were found among sequenced ITS regions from individual host amoeba isolates. In contrast, the ITS region of its endosymbiont revealed significantly lower levels of intra-genomic nucleotide diversity (Pi=0.0028-0.0056) compared with the host N. pemaquidensis. Phylogenetic and ParaFit coevolution analyses involving N. pemaquidensis isolates and their respective endosymbionts confirmed a significant coevolutionary relationship between the two protists. The observation of non-shared microheterogeneity and coevolution emphasizes the complexity of the interactions between N. pemaquidensis and its obligate endosymbiont.
authors.affiliation: AVC Lobster Science Centre, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Prince Edward Island, C1A 4P3, Canada.
authors.forename: Charles G B
authors.initials: CG
authors.lastname: Caraguel
authors.forename: Charles J
authors.initials: CJ
authors.lastname: O'Kelly
authors.forename: Pierre
authors.initials: P
authors.lastname: Legendre
authors.forename: Salvatore
authors.initials: S
authors.lastname: Frasca
authors.forename: Rebecca J
authors.initials: RJ
authors.lastname: Gast
authors.forename: Béatrice M
authors.initials: BM
authors.lastname: Després
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Cawthorn
authors.forename: Spencer J
authors.initials: SJ
authors.lastname: Greenwood
mesh_terms: D000818:Animals; D004275:DNA, Ribosomal / Q000235:genetics*; D021903:DNA, Ribosomal Spacer / Q000235:genetics; D019143:Evolution, Molecular; D014644:Genetic Variation; D016840:Lobosea / Q000145:classification / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D012340:RNA, Ribosomal, 5.8S / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D004275:DNA, Ribosomal; D021903:DNA, Ribosomal Spacer; D012340:RNA, Ribosomal, 5.8S