Deep divergence among subgenera of Gyrodactylus inferred from rDNA ITS region.
This paper adds new insight to a molecular phylogeny of Gyrodactylus, based on a complete sequence of the ITS rDNA region of 4 subgenera and a more detailed molecular analysis. We propose a hierarchical approach in elucidating the phylogeny of this species-rich genus. A total of 37 sequences (915-1239 bp) from 10 representative species from 4 out of 6 subgenera, as defined by Malmberg (1970), are included in the analysis. Genetic differences observed at the 5.8S locus provide objective criteria to separate (sub)genera, while deep genetic differences of the spacers form a sound basis for species-specific identification. We demonstrate that each Gyrodactylus subgenus possesses a unique sequence of the 5.8S gene. Thus, there is concordance between the 5.8S gene and the excretory system used by Malmberg (1970) as a diagnostic character of subgenus status. At the species level, there is a discrepancy between morphological and molecular variation. Whereas the morphological variation, expressed in the shape and size of the attachment apparatus, is very low, the molecular variation, expressed at the I
Zietara
M S
MS
Laboratory of Aquatic Ecology, Katholieke Universiteit Leuven, Belgium. zietara@biotech.univ.gda.pl
Huyse
T
T
Lumme
J
J
Volckaert
F A
FA
D000818:Animals; D001483:Base Sequence; D018509:DNA, Helminth / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification; D021903:DNA, Ribosomal Spacer / Q000737:chemistry / Q000235:genetics*; D014644:Genetic Variation; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012340:RNA, Ribosomal, 5.8S / Q000737:chemistry / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid; D014200:Trematoda / Q000737:chemistry / Q000145:classification* / Q000235:genetics
D018509:DNA, Helminth; D021903:DNA, Ribosomal Spacer; D012340:RNA, Ribosomal, 5.8S