Phylogenetic affinities of Diplonema within the Euglenozoa as inferred from the SSU rRNA gene and partial COI protein sequences.
In order to shed light on the phylogenetic position of diplonemids within the phylum Euglenozoa, we have sequenced small subunit rRNA (SSU rRNA) genes from Diplonema (syn. Isonema) papillatum and Diplonema sp. We have also analyzed a partial sequence of the mitochondrial gene for cytochrome c oxidase subunit I from D. papillatum. With both markers, the maximum likelihood method favored a closer grouping of diplonemids with kinetoplastids, while the parsimony and distance suggested a closer relationship of diplonemids with euglenoids. In each case, the differences between the best tree and the alternative trees were small. The frequency of codon usage in the partial D. papillatum COI was different from both related groups; however, as is the case in kinetoplastids but not in Euglena, both the non-canonical UGA codon and the canonical UGG codon were used to encode tryptophan in Diplonema.
Maslov
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Department of Biology, University of California, Riverside 92521, USA. maslov@ucrac1.ucr.edu
Yasuhira
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Simpson
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D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D003062:Codon / Q000235:genetics; D018105:DNA, Kinetoplast / Q000235:genetics; D004272:DNA, Mitochondrial / Q000235:genetics; D003576:Electron Transport Complex IV / Q000235:genetics*; D056890:Eukaryota / Q000235:genetics*; D020459:Genes, rRNA; D008969:Molecular Sequence Data; D010802:Phylogeny; D016053:RNA, Protozoan / Q000302:isolation & purification
D003062:Codon; D018105:DNA, Kinetoplast; D004272:DNA, Mitochondrial; D016053:RNA, Protozoan; D003576:Electron Transport Complex IV