title: Three rDNA Loci-Based Phylogenies of Tintinnid Ciliates (Ciliophora, Spirotrichea, Choreotrichida).
abstract: To improve understanding of diversity, phylogeny and evolution in tintinnid ciliates, it is essential to link multiple molecular markers with properly identified and documented morphospecies. Accordingly, 54 tintinnid morphospecies/isolates mainly from the Yellow and East China Seas were collected and analysed. Using single-cell approaches, sequences were obtained for three rDNA loci (18S, ITS1-5.8S-ITS2, D1-D5 region of 28S). Twenty-six tintinnid morphospecies (29 isolates) are documented by micrographs, measurements, morphologically described, and compared with the original species description. Three rDNA loci-based phylogenetic analyses were then performed for these identified isolates. Sequences from 25 unidentified species/isolates were also included in the comparison of the three rDNA loci. Ribosomal DNA genes of the genus Leprotintinnus were analysed for the first time, showing that Leprotintinnus was closely related to Tintinnopsis radix and branched distinctly apart from the family Tintinnidiidae. Four novel clades (VI to IX) of the Tintinnopsis complex emerged in the 18S genealogies. Analyses of the relative variability in the ITS and 28S regions vs. the 18S rDNA showed that the ITS1-5.8S-ITS2 and ITS2 regions well co-varied with the 18S rDNA when the variations of the latter were less than 3%, whereas at difference of less than 1%, no correlation was found between the compared loci. These findings highlight the difficulties in using variable locus-based cut-off divergences in circumscribing tintinnid morphospecies.
authors: Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, 264003, China.
authors: Qianqian
authors: Q
authors: Zhang
authors: Department of Ecology and Evolution, University of Salzburg, Salzburg, 5020, Austria.
authors: Sabine
authors: S
authors: Agatha
authors: Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China.
authors: Wuchang
authors: W
authors: Zhang
authors: Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, 264003, China.
authors: Jun
authors: J
authors: Dong
authors: Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China.
authors: Ying
authors: Y
authors: Yu
authors: State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, 361005, China.
authors: Nianzhi
authors: N
authors: Jiao
authors: Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, 264003, China.
authors: Jun
authors: J
authors: Gong
mesh_terms: D044822:Biodiversity; D002681:China; D016798:Ciliophora / Q000145:classification* / Q000166:cytology / Q000235:genetics* / Q000302:isolation & purification; D016054:DNA, Protozoan / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics*; D005602:France; D014644:Genetic Variation; D008853:Microscopy; D010802:Phylogeny; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D012339:RNA, Ribosomal, 28S / Q000235:genetics; D012340:RNA, Ribosomal, 5.8S / Q000235:genetics; D012623:Seawater / Q000469:parasitology; D013045:Species Specificity
chemical_list: D016054:DNA, Protozoan; D004275:DNA, Ribosomal; D012337:RNA, Ribosomal, 18S; D012339:RNA, Ribosomal, 28S; D012340:RNA, Ribosomal, 5.8S
keywords: Barcoding; genetic diversity; marine protists; microzooplankton; multiple-locus phylogeny