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Unique phylogenetic position of Diplomonadida based on the complete small subunit ribosomal RNA sequence of Giardia ardeae, G. muris, G. duodenalis and Hexamita sp.
Author(s) -
Van Keulen Harry,
Gutell Robin R.,
Gates Michael A.,
Campbell Scott R.,
Erlandsen Stanley L.,
Jarroll Edward L.,
Kulda Jaroslav,
Meyer Ernest A.
Publication year - 1993
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.7.1.8422968
Subject(s) - biology , ribosomal rna , phylogenetic tree , giardia , giardia lamblia , phylogenetics , genetics , microbiology and biotechnology , gene
Complete small‐subunit rRNA (SSU‐rRNA) coding region sequences were determined for two species of the intestinal parasite Giardia: G. ardeae and G. muris , both belonging to the order Diplomonadida, and a free‐living member of this order, Hexamita sp. These sequences were compared to published SSU‐rDNA sequences from a third member of the genus Giardia, G. duodenalis (often called G. intestinalis or G. lamblia ) and various representative organisms from other taxa. Of the three Giardia sequences analyzed, the SSU‐rRNA from G. muris is the smallest (1432 bases as compared to 1435 and 1453 for G. ardeae and G. duodenalis , respectively) and has the lowest G + C content (58.9%). The Hexamita SSU‐rRNA is the largest in this group, containing 1550 bases. Because the sizes of the SSU‐rRNA are prokaryotic rather than typically eukaryotic, the secondary structures of the SSU‐rRNAs were constructed. These structures show a number of typically eukaryotic signature sequences. Sequence alignments based on constraints imposed by secondary structure were used for construction of a phylogenetic tree for these four taxa. The results show that of the four diplomonads represented, the Giardia species form a distinct group. The other diplomonad Hexamita and the microsporidium Vairimorpha necatrix appear to be distinct from Giardia.— van Keulen, H., Gutell, R. R., Gates, M. A., Campbell, S. R., Erlandsen, S. L., Jarroll, E. L., Kulda, J., Meyer, E. A. Unique phylogenetic position of Diplomonadida based on the complete small subunit ribosomal RNA sequence of Giardia ardeae, G. muris, G. duodenalis , and Hexamita sp . FASEB J. 7: 223‐231; 1993.