title: Phylogenetic information content of Copepoda ribosomal DNA repeat units: ITS1 and ITS2 impact.
abstract: The utility of various regions of the ribosomal repeat unit for phylogenetic analysis was examined in 16 species representing four families, nine genera, and two orders of the subclass Copepoda (Crustacea). Fragments approximately 2000 bp in length containing the ribosomal DNA (rDNA) 18S and 28S gene fragments, the 5.8S gene, and the internal transcribed spacer regions I and II (ITS1 and ITS2) were amplified and analyzed. The DAMBE (Data Analysis in Molecular Biology and Evolution) software was used to analyze the saturation of nucleotide substitutions; this test revealed the suitability of both the 28S gene fragment and the ITS1/ITS2 rDNA regions for the reconstruction of phylogenetic trees. Distance (minimum evolution) and probabilistic (maximum likelihood, Bayesian) analyses of the data revealed that the 28S rDNA and the ITS1 and ITS2 regions are informative markers for inferring phylogenetic relationships among families of copepods and within the Cyclopidae family and associated genera. Split-graph analysis of concatenated ITS1/ITS2 rDNA regions of cyclopoid copepods suggested that the Mesocyclops, Thermocyclops, and Macrocyclops genera share complex evolutionary relationships. This study revealed that the ITS1 and ITS2 regions potentially represent different phylogenetic signals.
authors.affiliation: Vavilov Institute of General Genetics, Russian Academy of Sciences, Gubkin Street. 3, Moscow 119991, Russia.
authors.forename: Maxim V
authors.initials: MV
authors.lastname: Zagoskin
authors.affiliation: Papanin Institute for Biology of Inland Waters, Russian Academy of Sciences, Borok 152742, Russia.
authors.forename: Valentina I
authors.initials: VI
authors.lastname: Lazareva
authors.affiliation: Papanin Institute for Biology of Inland Waters, Russian Academy of Sciences, Borok 152742, Russia ; Dubna International University for Nature, Society and Man, Universitetskaya Street 19, Dubna 141980, Russia.
authors.forename: Andrey K
authors.initials: AK
authors.lastname: Grishanin
authors.affiliation: Vavilov Institute of General Genetics, Russian Academy of Sciences, Gubkin Street. 3, Moscow 119991, Russia.
authors.forename: Dmitry V
authors.initials: DV
authors.lastname: Mukha
mesh_terms: D000818:Animals; D001499:Bayes Theorem; D033342:Copepoda / Q000235:genetics*; D021903:DNA, Ribosomal Spacer / Q000235:genetics*; D019143:Evolution, Molecular; D014644:Genetic Variation; D010802:Phylogeny; D012339:RNA, Ribosomal, 28S / Q000235:genetics; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics
chemical_list: D021903:DNA, Ribosomal Spacer; D012339:RNA, Ribosomal, 28S